the red corral (proctor ranch) local fauna (pliocene

Bulletin 73

New Mexico Museum of Natural History & Science

A Division of the DEPARTMENT OF CULTURAL AFFAIRS

THE RED CORRAL (PROCTOR RANCH) LOCAL FAUNA (PLIOCENE, BLANCAN) OF OLDHAM COUNTY, TEXAS

by

GERALD E. SCHULTZ

Albuquerque, 2016

Bulletin 73

New Mexico Museum of Natural History & Science

A Division of the DEPARTMENT OF CULTURAL AFFAIRS


GERALD E. SCHULTZ

New Mexico Museum of Natural History & ScienceAlbuquerque, 2016

STATE OF NEW MEXICODepartment of Cultural AffairsVeronica Gonzales, Secretary

NEW MEXICO MUSEUM OF NATURAL HISTORY AND SCIENCEMargaret Marino, Executive Director

BOARD OF TRUSTEESSusanna Martinez, Governor, State of New Mexico, ex officio

Margaret Marino, Executive Director, ex officioGary Friedman, President

Leonard DudaMaya Elrick, Ph.D.

Peter F. Gerity, Ph.D.Deron Knoner

Laurence Lattman, Ph.D.Viola Martinez

Mike MertzMarvin Moss

John Montgomery, Ph.D.Jennifer Riordan

Laura Smigielski-GarciaSteve West

Cover illustration: Right dentary of Miracinonyx studeri (see Figure 30)

Original PrintingISSN: 1524-4156

Available from the New Mexico Museum of Natural History and Science, 1801 Mountain Road NW, Albuquerque, NM 87104; Telephone (505) 841-2800; Fax (505) 841-2866; www.nmnaturalhistory.org

NMMNH Bulletins online at: http://nmnaturalhistory.org/bulletins

BULLETIN OF THE NEW MEXICO MUSEUM OF NATURAL HISTORY AND SCIENCE

EDITORS

Spencer G. Lucas New Mexico Museum of Natural History and Science, Albuquerque, NM, USA (NMMNHS)Robert Sullivan NMMNHSLawrence H. Tanner Le Moyne College, Syracuse, NY, USA

MANAGING EDITOR

Asher J. Lichtig NMMNHS

ASSOCIATE EDITORS

Guillermo Alvarado Asociación Costarricense de Geotecnica, San José, Costa Rica Marco Avanzini Museo Tridentino di Scienze Naturali, Trento, ItalyDavid Berman Carnegie Museum of Natural History, Pittsburgh, PA, USABrent Breithaupt Laramie, WY, USAWilliam DiMichele National Museum of Natural History, Washington, D.C., USAJohn R. Foster Museum of Western Colorado, Grand Junction, CO, USAGerard Gierlinski Polish Geological Institute, Warsaw, PolandJean Guex University of Lausanne, Lausanne, SwitzerlandJerald D. Harris Dixie State College, St. George, UT, USAAndrew B. Heckert Appalachian State University, Boone, NC, USAAdrian P. Hunt Flying Heritage Collection, Everett, WA, USAHendrik Klein Neumarkt, GermanyKarl Krainer University of Innsbruck, Innsbruck, AustriaMartin G. Lockley University of Colorado at Denver, Denver, CO, USAClaudia Marsicano Universidad de Buenos Aires, Buenos Aires, ArgentinaGary S. Morgan NMMNHSDonald R. Prothero Occidental College, Los Angeles, CA, USASilvio Renesto Università degli Studi dell’Insubria, Varese, ItalyJoerg W. Schneider Technical University BergAkademie of Freiberg, Freiberg, GermanyJingeng Sha Nanjing Institute of Geology and Palaeontology, Nanjing, ChinaSebastian Voigt Urweltmuseum GEOSKOP/Burg Lichtenburg, Thallichtenberg, GermanyRalf Werneburg Naturhistorisches Museum Schloss Bertholdsburg, Schleusingen, GermanyRichard S. White, Jr. International Wildlife Museum, Tucson, AZ, USA

NEW MEXICO MUSEUM OF NATURAL HISTORY AND SCIENCE BULLETINS

37. The Triassic-Jurassic Terrestrial Transition, 2006. edited by Jerry D. Harris, Spencer G. Lucas, Justin A. Spielmann, Martin G. Lockley, Andrew R.C. Milner and James I. Kirkland, 607 pp.38. Pennsylvanian-Permian Fusulinaceans of the Big Hatchet Mountains, New Mexico, 2006. by Garner L. Wilde, 331 pp.39. Upper Aptian-Albian Bivalves of Texas and Sonora: Biostratigraphic, Paleoecologic and Biogeographic Implications, 2007. edited by Robert W. Scott, 39 pp.40. Triassic of the American West, 2007. edited by Spencer G. Lucas and Justin A. Spielmann, 247 pp.41. The Global Triassic, 2007. edited by Spencer G. Lucas and Justin A. Spielmann, 415 pp.42. Cenozoic Vertebrate Tracks and Traces, 2007. edited by Spencer G. Lucas, Justin A. Spielmann and Martin G. Lockley, 330 pp.43. The Late Triassic archosauromorph Trilophosaurus, 2008. by Justin A. Spielmann, Spencer G. Lucas, Larry F. Rinehart and Andrew B. Heckert, 177 pp.44. Neogene Mammals, 2008. edited by Spencer G. Lucas, Gary S. Morgan, Justin A. Spielmann and Donald R. Prothero, 442 pp.45. The Paleobiology of Coelophysis bauri (Cope) from the Upper Triassic (Apachean) Whitaker quarry, New Mexico, with detailed analysis of a single quarry block, 2009. by Larry F. Rinehart, Spencer G. Lucas, Andrew B. Heckert, Justin A. Spielmann and Matthew D. Celeskey, 260 pp.46. The taxonomy and paleobiology of the Late Triassic (Carnian-Norian: Adamanian-Apachean) drepanosaurs (Diapsida: Archosauromorpha: Drepanosauromorpha, 2010. by Silvio Renesto, Justin A. Spielmann, Spencer G. Lucas and Giorgio Tarditi Spagnoli, 81 pp.47. Ichnology of the Upper Triassic (Apachean) Redonda Formation, east-central New Mexico, 2010. by Spencer G. Lucas, Justin A. Spielmann, Hendrik Klein and Allan J Lerner, 75 pp.48. New Smithian (Early Triassic) ammonoids from Crittenden Springs, Elko County, Nevada: Implications for taxonomy, biostratigraphy and biogeography, 2010. by James F. Jenks, Arnaud Brayard, Thomas Brühwiler and Hugo Bucher, 41 pp.49. Carboniferous-Permian transition in Cañon del Cobre, northern New Mexico, 2010. edited by Spencer G. Lucas, Jörg W. Schneider and Justin A. Spielmann, 229 pp.50. Review of the tetrapod ichnofauna of the Moenkopi Formation/Group (Early-Middle Triassic) of the American Southwest, 2010. by Hendrik Klein and Spencer G. Lucas, 67 pp.51. Crocodyle tracks and traces, 2010. edited by Jesper Milàn, Spencer G. Lucas, Martin G. Lockley and Justin A. Spielmann, 244 pp.52. Selachians from the Upper Cretaceous (Santonian) Hosta Tongue of the Point Lookout Sandstone, central New Mexico, 2011. by Jim Bourdon, Keith Wright, Spencer G. Lucas, Justin A. Spielmann and Randy Pence, 54 pp.53. Fossil Record 3, 2011. edited by Robert M. Sullivan, Spencer G. Lucas and Justin A. Spielmann, 736 pp.54. Ichnology of the Mississippian Mauch Chunk Formation, eastern Pennsylvania, 2012. by David L. Fillmore, Spencer G. Lucas and Edward L. Simpson, 136 pp.55. Tetrapod fauna of the Upper Triassic Redonda Formation, east-central New Mexico: The characteristic assemblage of the Apachean land-vertebrate faunachron, 2012. by Justin A. Spielmann and Spencer G. Lucas, 119 pp.56. Revision of the Lower Triassic tetrapod ichnofauna from Wióry, Holy Cross Mountains, Poland, 2012. by Hendrik Klein and Grzegorz Niedzwiedzki, 62 pp.57. Vertebrate Coprolites, 2012. edited by Adrian P. Hunt, Jesper Milàn, Spencer G. Lucas and Justin A. Spielmann, 387 pp.58. A new archaic basking shark (Lamniformes: Cetorhinidae) from the late Eocene of western Oregon, U.S.A., and description of the dentition, gill rakers and vertebrae of the recent basking shark Cetorhinus maximus (Gunnerus), 2013. by Bruce J. Welton, 48 pp.59. The Carboniferous-Permian transition in central New Mexico, 2013. edited by Spencer G. Lucas, W. John Nelson, William A. DiMichele, Justin A. Spielmann, Karl Krainer, James E. Barrick, Scott Elrick and Sebastian Voigt, 389 pp.60. The Carboniferous-Permian transition, 2013. edited by Spencer G. Lucas, William A. DiMichele, James E. Barrick, Joerg W. Schneider and Justin A. Spielmann, 465 pp.61. The Triassic System: New Developments in Stratigraphy and Paleontology, 2013. edited by Lawrence H. Tanner, Justin A. Spielmann and Spencer G. Lucas, 612 pp. 62. Fossil Footprints of Western North America, 2014. edited by Martin G. Lockey and Spencer G. Lucas, 508 pp. 63. Variation in the Dentition of Coelophysis bauri, 2014. by Lisa G. Buckley and Philip J. Currie, 73 pp.64. Conodonts from the Carnian-Norian Boundary (Upper Triassic) of Black Bear Ridge, Northeastern British Columbia, Canada, 2014, by Michael J. Orchard, 139 pp.65. Carboniferous-Permian Transition in the Robledo Mountains Southern New Mexico, 2015, edited by Spencer G. Lucas and William A. DiMichele, 167 pp.66. The Marine Fish Fauna of the Middle Pleistocene Port Orford Formation and Elk River Beds, Cape Blanco, Oregon, 2015, by Bruce J. Welton, 45 pp.67. Fossil Record 4, 2015. edited by Robert M. Sullivan and Spencer G. Lucas, 332 pp.68. Fossil Vertebrates in New Mexico, 2015, edited by Spencer G. Lucas and Robert M. Sullivan, 438 pp.69. The Pennsylvanian System in the Mud Springs Mountains, Sierra County, New Mexico, USA, 2016, by Spencer G. Lucas, Karl Krainer, James E. Barrick and Daniel Vachard, 58 pp.70. Eocyclotosaurus appetolatus, a Middle Triassic Amphibian, 2016, by Rinehart and Lucas, 118 pp.71. Cretaceous Period: Biotic Diversity and Biogeography, 2016, edited byAshu Khosla and Spencer G. Lucas, 330 pp. 72. Rotten Hill: a Late Triassic Bonebed in the Texas Panhandle, USA, 2016, by S.G. Lucas, L.F. Rinehart, A.B. Heckert, A.P. Hunt and J.A. Spielmann, 97 pp.

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Gerald E. Schultz, 2016, The Red Corral (Proctor Ranch) Local Fauna (Pliocene, Blancan) of Oldham County, Texas. New Mexico Museum of Natural History and Science Bulletin 73.


GERALD E. SCHULTZ

Department of Life, Earth, and Environmental Science, WT Box 60808. West Texas A&M University, Canyon, Texas 79016. Email: gschultz@wtamu. edu

Abstract—The Red Corral (Proctor Ranch) Local Fauna (LF) is a large and diverse assemblage of Pliocene (late Blancan) vertebrates and freshwater mollusks from Oldham County in the northwest part of the Texas Panhandle in the Rita Blanca Formation. To date the fauna is poorly known and little has been published. Large mammals were collected from fluvial and pond or marsh deposits on the Foy Proctor Ranch in 1952 by the Frick Laboratory in New York City and many of these are described for the first time in this study. Freshwater mollusks were collected and described in 1960 by Dwight Taylor of the U. S. Geological Survey, who coined the name Red Corral Local Fauna. During the summers of 1966-1969, about 40 tons of matrix were screen washed from two quarry sites by the author and field parties from West Texas A&M University to yield a large microvertebrate fauna including as yet unstudied remains of small fish, frogs, toads, salamanders, turtles, snakes, lizards and water or marsh birds. Over 45 species of mammals were obtained and are reported here. Soricomorphs include a medium-sized shrew, Sorex taylori, represented by over 50 dentaries (minimum of 27 individuals), and the mole Scalopus (Hesperoscalops) rexroadi. A fragmentary bat dentary (cf. Molossidae) was found. Lagomorphs include Hypolagus (3 species), Pewelagus, and Sylvilagus, initially studied and reported by the late John A. White, and the first North American record of Pliopentalagus. Rodents include Procastoroides sweeti, Spermophilus (sensu lato), Geomys, Prodipodomys, Perognathus, Peromyscus, Reithrodontomys, Onychomys, Bensonomys, Sigmodon, and Neotoma. Sigmodon minor /medius is the most abundant rodent, being represented by nearly 100 dentaries (minimum of 46 individuals) and several hundred isolated teeth. The Neotoma teeth are smaller than those from the Rexroad Locality 3 LF in Kansas and more nearly match in size those of Neotoma fossilis from Arizona. No arvicolid rodents were found. A concentration of fragmentary geomyid, heteromyid, cricetid, and leporid dentitions at one site suggests that owls may have hunted these upland forms and concentrated their skeletal remains in such a way that they were abundantly preserved in a low energy fluvial environment although no actual fossil owl pellets were found. Carnivoranes include Canis lepophagus, Urocyon, Borophagus diversidens, Taxidea, Trigonictis cookii, Bassariscus, Homotherium, and a large cat, Miracinonyx studeri, represented by skull fragments, dentitions, and associated postcranial elements. Other taxa include Megalonyx, Stegomastodon mirificus, Nannippus peninsulatus, Equus, Platygonus, Camelops, Hemiauchenia, Capromeryx, and a cervid. Of unique interest is one of the northernmost Blancan occurrences of the ground sloth, Paramylodon cf. garbanii, an immigrant from South America during the second phase of the Great American Biotic Interchange (GABI), which began about 3 Ma ago. No glyptodonts were found, however. Radiometrically datable ash beds are absent. Paleomagnetic signatures of the fossil-bearing layers at two quarry sites are weak, but several normal polarity samples suggest assignment to the Gauss chron between 3. 20-2. 58 Ma. Biocorrelation of the Red Corral LF with other North American faunas indicates assignment to the late Blancan NALMA (contra early Blancan in Janis et al., 1998, p. 637, SP1G; Janis et al., 2008, p. 713, SP1G). There are many similarities between the Red Corral LF and other Blancan faunas in southwest Kansas and Nebraska as well as in Arizona and New Mexico. The immediate habitat at the sites appears to have been a fluvial or lacustrine system bounded by a prairie mosaic.

INTRODUCTIONBlancan age faunas have been known from the Texas Panhandle

for over a century (Fig. 1). Fossil vertebrates from the region around Mt. Blanco in Crosby County, Texas, were described by Cope (1893). Since then, many institutions have collected there, and an extensive literature has developed on the Blanco LF, with the most significant collections being reported by Meade (1945) and Dalquest (1975). Wood et al. (1941) designated the Blanco LF as the type faunal locality of the Blancan Provincial Age, which later became designated a North American land mammal “age” (Evernden et al., 1964).

In 1936, Blancan vertebrates were discovered in North Cita Canyon, Randall County, Texas, about 22. 4 km (14 miles) southeast of Amarillo. The Cita Canyon LF (Johnston and Savage, 1955) is a large and diverse fauna collected initially by the Panhandle-Plains Historical Museum in Canyon, Texas, using digging crews hired through the Works Progress Administration (WPA) in the 1930s. An extensive literature has developed dealing mostly with particular taxonomic members of the fauna (e. g. Johnston, 1938; Stirton and Christian, 1940, 1941; Savage, 1955, 1960; Mawby, 1965; Hirschfeld and Webb, 1968; Gillette and Ray, 1981; Wang et al., 1999; Tedford et al., 2009). Many taxa remain unreported or undescribed, and a general review of the fauna is underway (Schultz, in prep. ).

Evans and Meade (1945) mentioned the presence of Blancan mammals in what they named the Rita Blanca beds from localities west and northwest of Channing, Hartley County, Texas, and Norton (1954) reported a small Blancan fauna from near Hereford (Hereford Dump LF) in Deaf Smith County, Texas. Both faunas were cited by Johnston and Savage (1955). Finally, although it is technically south of the Panhandle, the Beck Ranch LF (early Blancan) was described by Dalquest (1978) from a site near Snyder in Scurry County, Texas.

In 1951, 1952, and 1953, N. Z. Ward and a party from the Frick

Laboratory in New York City collected vertebrate fossils from several localities along Rita Blanca Creek and its tributaries about 11 km (7 miles) west and northwest of Channing in Hartley County (Fig. 2) and also from several localities on the Foy Proctor Ranch on the west side of the valley of Punta de Agua Creek (below its junction with Rita Blanca Creek) in northern Oldham County, about 16 km (10 miles) southwest of Channing (Figs. 2-3). Only a few of these fossils have been described, including a sloth (Hirschfeld and Webb, 1968), a bone-eating dog (Wang et al., 1999), and a coyote (Tedford et al., 2009). In the summer of 1954, D. E. Savage and a field party from the University of California Museum of Paleontology (UCMP) in Berkeley visited the Proctor Ranch quarries, collected scraps of mammalian fossils, and observed the presence of mollusks at one site (Proctor Pit D). Later in the same year, C. W. Hibbard from the University of Michigan in Ann Arbor went to the site to collect the mollusks. D. W. Taylor collected additional mollusks from Pit D in the summer of 1957 (Loc. T 57-34 and U. S. G. S. Cenozoic Locality 21040). Paleoecological analyses of the mollusks were published by Herrington and Taylor (1958) and Taylor (1960), who noted a similarity to the molluscan fauna from the Rexroad LF sites in Meade County, Kansas, 235 km (146 miles) to the northeast. During the course of wet-screening for the mollusks, a few isolated teeth of small rodents and rabbits were also discovered and are now housed in the collections of the University of Michigan Museum of Paleontology (UMMP). The name Red Corral LF was coined by Taylor (1960) for the mammals and mollusks known from these localities because of a prominent red painted cattle pen located 1. 6 km (1 mile) south of the quarries. The present study was begun in an attempt to obtain a significant microvertebrate fauna from Pit D and to recover additional remains of large mammals from some of the other quarries or pits. During the summers of 1966, 1967, 1968, and 1969, a total of 40 tons of matrix were collected and screen washed from Pits

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mapping and correlation of units over any great distance is extremely difficult. The best exposures are seen in small cuestas capped by white lacustrine clays and caliches, which collectively show a regional dip to the SSW toward the Canadian River as a result of basement faulting and/or subsurface dissolution and surface collapse (Schmude, 1993).

On the Proctor Ranch, the fossil-bearing sites lie in a sequence of interbedded fluviatile and lacustrine or pond and marsh deposits exposed on hill slopes or along small tributaries draining NE toward Punta de Agua Creek below its junction with Rita Blanca Creek (Fig. 3). Fossil quarry sites are 100 to 300 meters apart and correlation between them is facilitated by thin beds of intercalated caliche. Pits B and C are at approximately the same stratigraphic level (Fig. 4). A prominent, gently dipping caliche unit (Caliche B) above these pits can be traced around a hillside where it disappears beneath the floor of Pit D (Fig. 5). Despite the separation by Caliche B, the time differential between Pits B and C beneath the caliche and Pit D above the caliche is not pronounced, as indicated by the similarity of rodent species from Pits C and D (Table 1). Consequently, for the purposes of biochronology and palaeoecological reconstruction, the mammalian assemblages from Pits A, B, C, and D as well as WT Locality 5 were combined and treated as a homogeneous community, the Red Corral LF.

In general, the fossil-bearing sediments are aligned along the north limb of a monocline with a roughly east-west axis that lies in the valley south of the fossiliferous strike ridge, which can be traced eastward for about 0. 8 km (0. 5 mile) before being eroded by the broad valley of Punta de Agua Creek. Dips of up to 10 degrees to the south or southwest can be observed in places along the strike ridge (Figs. 6, 10). To the west, the fossiliferous units pass beneath the upland surface. Buff colored silty sands to the north may represent older sediments within the Rita Blanca Formation or possibly the Ogallala Formation into which the Rita Blanca basin was excavated.

NOMENCLATURE AND DESCRIPTION OF FOSSIL LOCALITIES

All fossil sites are located on the Torrey House, 7 ½ minute quadrangle topographic map published by the U. S. Geological Survey. The sites are all in Oldham County, about 0. 8 km (0. 5 mile) south of the Hartley-Oldham County line. The ranch is privately owned – currently by Mike Smith of Amarillo, Texas. Access is limited and permission must be obtained from the owner or the foreman in residence. Red Corral LF sites (Blancan):

1) Proctor Pit A of Frick = WT Locality 4 (41OL-P4) = P107A

C and D by a party of students from West Texas State University (now West Texas A&M University; WT) in Canyon using the wet-screening methods developed by Hibbard (1949). The results are reported here.

GEOLOGICAL SETTINGThe fossiliferous sediments from which the Red Corral LF was

collected are considered to be a part of the Rita Blanca Formation of Late Cenozoic age. These beds, which were named and described by Evans and Meade (1945), comprise a sequence of basin-fill deposits exposed primarily in denuded areas bordering intermittent tributaries on the northeast side of the valley of Rita Blanca Creek, about 11 km (7 miles) WNW of Channing in SE Hartley County, Texas, and 1. 6 to 3. 2 km (1 to 2 miles) north of Farm-to-Market Road 767, which runs from Channing to Romero (Johnston and Savage, 1955). The lower part of this sequence consists of laminated gray, lacustrine clays and interbedded sandy lenses containing fossil leaves, insects, and small fish (Anderson and Kirkland, 1969). Less than 1. 6 km (1 mile) to the north, the sequence consists of reddish sands and greenish silty clays containing late Hemphillian camel bones and white, flaggy, penecontemporaneously deformed beds of lacustrine, sandy limestone bearing camel track fillings on their undersides. Higher in the section are calcareous sandstones, yellow sands, mudstones, and bentonitic or lignitic clays which have yielded fossil horses, camels, mastodons, and other mammals of Blancan age. Near the top of the sequence on the divide between Rita Blanca Creek on the west and its main tributary, Sand Creek, on the east is a deposit of Cerro Toledo X volcanic ash derived from New Mexico and dated at 1. 2-1. 5 Ma (Izett et al., 1981). Remains of mammoth have also been recovered from high in the section, indicating a Pleistocene age for the upper-most sediments in the sequence. According to information provided by the United States Geological Survey, the Rita Blanca Formation makes up about two per cent of the area in Hartley County. As mentioned above, the Frick Laboratory made extensive collections from several quarries in this area. Smaller collections have also been made by the West Texas Museum in Lubbock, the Panhandle-Plains Historical Museum in Canyon, Texas, and the University of California in Berkeley (Johnston and Savage, 1955).

South of Farm-to-Market Road 767 on the former Proctor Ranch and also SSE of Channing near U. S. Highway 385 in Oldham County, Texas, the Rita Blanca Formation is poorly exposed. As a result,

FIGURE 1. Partial outline map of the Texas Panhandle showing location of Blancan faunal sites. Abbreviations: Ch = Channing localities; RC = Red Corral (Proctor Ranch); CC = Cita Canyon; H = Hereford Dump; B = Blanco.

FIGURE 2. Map of Channing, Texas area showing locations of Channing Rita Blanca/Sand Creek sites (Ch) and Red Corral (Proctor Ranch) sites (RC).

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FIGURE 3. Topographic map of part of the Proctor Ranch showing Frick Laboratory Pits A, B, C, and D and WTAMU localities 5, 6 (Pleistocene), and 7 (Rentfro Pit 2 of Frick).

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FIGURE 4. Stratigraphic sections at Pit B and Pit C. Abbreviations: N = normal paleomagnetic polarity sample taken next to fossil bone at Pit C.

of the Panhandle-Plains Historical Museum (Fig. 3). The site is in the NE 1/4 SE 1/4 SW 1/4 sec. 3, Blk. 22, CSS (Capital Syndicate Subdivision). Fossils occur in the lower part of a 3 m (10 ft) thick bed of greenish-gray sandstone between two white, weathered sandy limestone units. N. Z. Ward collected fossils of horse and small camel from the site. A few fossil horse remains were collected by the WT field party at the SW end of a small ridge. No microfauna was obtained.

2) Proctor Pit B = WT Locality 3 (41OL-P3) = P107B = Locality 7 of Savage (UCMP). The site is about 215 m (705 ft) east of Pit A and about 110 m (360 ft) northeast of Pit D on the north side of a small hill (Fig. 3). The site is in the NW 1/4 SW 1/4 SE 1/4 sec. 3, Blk. 22, CSS. GPS coordinates are lat. 35. 61954 degrees N. and long. 102. 48405 degrees W. Ward collected fossils of horse and small camel, a sloth tooth, and mandibles of a machairodont, a coyote, and a badger from a 1. 5 m (5 ft) cut at the base of a mostly covered 6 m (20 ft) sequence of greenish-gray fine sand which is overlain by a thin caliche and gravel. The WT field party did not attempt to recover a microfauna from this site.

3) Proctor Pit C = WT Locality 1 (41OL-P1) = P107C = Loc. 5 of Savage (UCMP V-5327). The site is about 160 m (525 ft) east of Pit B and about 255 m (836 ft) ENE of Pit D along a hill slope on the west side of a north-draining ravine (Figs. 3, 7, 8, and 9). and is in the NE 1/4 SW 1/4 SE 1/4 sec. 3, Blk. 22, CSS. GPS coordinates are lat. 35. 61973 degrees N. and 102. 48245 degrees W. Ward collected horse, small camel, stegomastodont, borophagine dog, two kinds of sloth, and an antilocaprid tooth from a 4. 5 m (15 ft) unit of mainly greenish-gray silty sand with some alternating layers of tan to buff colored sand. The WT field party collected additional macrovertebrates including horse, large and small camel, stegomastodont, borophagine, and the jaws and some postcranial bones of a large jaguar-sized cat. About 12 tons of

matrix were collected from the upper part of the quarry, which, when screen washed, yielded a microfauna containing numerous teeth and jaw fragments of geomyids, heteromyids, cricetines, and leporids. Apparently most of the surface material collected by the Panhandle-Plains Historical Museum and by D. E. Savage and the UCMP field party came from this site. Lindsay et al. (1975) obtained a normal paleomagnetic signature on a sediment sample from the fossil-bearing layer.

4) Proctor Pit D = WT Locality 2 (41OL-P2) = P107D = Loc. 6 of Savage (UCMP) = D. W. Taylor’s mollusk locality (T 57-34 and U. S. G. S. Cenozoic Locality 21040). The site is about 215 m (705 ft) SE of Pit A and 110 m (360 ft) SW of Pit B along the east side of a small ravine that runs into a larger tributary that enters Punta de Agua Creek about 1. 6 km (1 mile) to the northeast (Figs. 3, 11, 12, and 13) and is in the SW 1/4 SW 1/4 SE 1/4 sec. 3, Blk. 22, CSS. GPS coordinates are lat. 35. 61875 degrees N. and long. 102. 48485 degrees W. The fossiliferous unit consists of 1. 5 m (5 ft) of chocolate brown mudstone or siltstone grading upward to a lavender and yellow, papery thin shale, that contains many crushed snails and appears to have been deposited in a pond and marsh habitat. In places the papery layers are impregnated with calcium carbonate giving it a hard, white, blocky or punky appearance. This unit is fossiliferous throughout and produced the mollluscan fauna reported by Taylor (1960) along with a few rodent and rabbit teeth cataloged in the UMMP collections. A few macrovertebrates including horse, small camel, borophagine dog, beaver, peccary, antilocaprid, and the mandible of a large jaguar-sized cat were collected by Ward for the Frick Laboratory. About 28 tons of matrix were collected and screen washed by a WT field party to yield the fauna here reported. Lindsay et al. (1975) obtained a weak and dubious normal paleomagnetic signature from a sediment sample from

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FIGURE 5. Stratigraphic section at Pit D showing caliche B dipping beneath exposed section at Pit D. Abbreviations: N = north, S = south, ?N = weak, probably normal paleomagnetic polarity sample taken, R = reversed paleomagnetic sample taken.

FIGURE 6. View to the northeast from Pit C showing regional dip of beds to the south at about 10 degrees. Punta de Agua Creek in the distance (below junction with Rita Blanca Creek).

FIGURE 7. View of Pit C (at far right with white-shirted man for scale) on the west side of small arroyo. Large outcrop at left did not yield any fossils.

the fossil-bearing unit. 5) WT Locality 5 (41OL-P5). New mollusk site (Fig. 3). Center,

SE 1/4 SW 1/4 sec. 3, Blk. 22, CSS about 215 m (705 ft)west of Pit D. Small mollusks are abundant in exposures of silty clay on the south side of a small NE draining ravine. Equus jaws and a large camel radius were collected north of this ravine. The site appears to be at the same stratigraphic level as Pit D. Other sites:

1) WT Locality 6 (41OL-P6). Pleistocene vertebrate site higher in the section (Fig. 3) located in the SE 1/4 SE 1/4 SW 1/4 sec. 3, Blk. 22, CSS.

2) WT Locality 7 (41OL-P7). Rentfro Pit 2 of Frick. Although

of Blancan age, the site is not considered part of the Red Corral LF. It is located 0. 8 km (0. 5 mile) east of the Proctor pits along the top of the strike ridge containing those pits (Fig. 3). The site is in the SW 1/4 SW 1/4 sec. 52, Blk. B5, E . L. & Ry. Co. Survey. Fossil horse teeth were collected by Ward and by the WT field party from a small exposure of greenish-gray sandstone 0. 3-0. 6 m (10-20 ft) below a thin-bedded ostracod-bearing limestone.

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FIGURE 8. View of Pit C (below tarp).

FIGURE 9. View of Pit C. Students sacking dirt to be screen washed.

FIGURE 10. View to the northeast from Pit D showing regional dip of beds to the south at about 10 degrees.

FIGURE 11. View of Pit D on east side of small arroyo. Fossils occur in chocolate brown shale in middle of section to the right of shovel.

FIGURE 12. View of Pit D. Stack of matrix-filled burlap sacks for scale.

FIGURE 13. View to the south along face of Pit D at left. Man standing on top of dirt pile to the right of the trench for scale. METHODS, MATERIALS, AND ABBREVIATIONS

Most of the specimens in the fauna were collected by the author and field parties and are housed in the collections of the Department of Life, Earth, and Environmental Science, West Texas A&M University in Canyon. Only the mammals have been assigned catalog numbers. In the following fossil descriptions, specimen numbers without an acronym are from WTAMU (formerly West Texas State University). Some earlier references may use the prefix WTSU, and some of the tables included here may use the prefix WT. When a specimen number appears at the beginning of a sentence, it is preceded by the

institutional acronym (abbreviated WT for WTAMU). Specimens from other institutions either described herein or referred to in the text and/or tables for comparison bear the following acronyms: ANSP (Academy of Natural Sciences Philadelphia); F:AM (Frick: American Museum Mammals collection in the American Museum of Natural History); IGM (Instituto de Geologia, Mexico); KU (University of Kansas in Lawrence); UCMP (University of California Museum of Paleontology in Berkeley); UMMP (University of Michigan Museum

7of Paleontology in Ann Arbor); USNM (United States National Museum, Washington DC). All measurements are in millimeters unless otherwise indicated. Small specimens were measured to the nearest 0. 05 mm using a calibrated ocular scale in a Bausch and Lomb binocular microscope. Large specimens were measured to the nearest 0. 05 mm using a standard dial calipers or, in a few cases, a metric bar scale for long bones. Abbreviations used throughout the text and in the tables include AP = anteroposterior; L = length; LF = local fauna; N = sample size; OR = observed range; SD = standard deviation; TW = transverse width; W = width. Other abbreviations and measurements are explained in the text or table captions.

SYSTEMATIC PALEONTOLOGY Class Osteichthyes – tentative identification of ictalurid (catfish)

bones was made by Gerald Smith of the UMMP. Class Amphibia – preliminary identifications were made by

the late J. Alan Holman of Michigan State University (personal communication). Urodeles include two kinds of Ambystoma. Anurans include Scaphiopus (based on a sacrococcyx), Acris (ilium), Hyla (ilium), Rana (numerous ilia), and Bufo cf. woodhousei. Most of the fossils were obtained from Pit D.

Class Reptilia – preliminary identifications were made by the late J. Alan Holman. Chelonians, based on fragments of carapace or plastron, include Geochelone (now Hesperotestudo) large sp., H. turgida, Pseudemys (now Trachemys), a small emydid (possibly Chrysemys), Terrapene, Kinosternon, Chelydra, and possibly Trionyx (now Apalone). Lizards include Phrynosoma (horns), a sceloporine, Cnemidophorus (now Aspidoscelis), and Eumeces (now relegated to several genera; two species). Snakes, identified primarily on vertebrae, include a crotalid (now crotaline), Pituophis, and numerous natricines including at least two species (a ribbon snake and the genus Natrix- now Nerodia). Most of the fossils were obtained from Pit D and a few from Pit C. Numerous parts of a Kinosternon carapace were found at Locality 5.

Class Aves – preliminary identifications were made by Robert Weigel of Illinois State University. Pit C produced a distal end and the lateral spur of a tarsometatarsus of a turkey, probably Meleagris, as well as a few small unidentifiable bones and egg shell fragments. Most of the fossils were recovered from Pit D and include coracoids, carpometacarpi, beaks and other elements of coot, rail, gallinule (swamp hen), duck, teal, ibis or heron, swan, and even owl. Numerous egg shell fragments were also found.

Class Mammalia – over 45 species of mammals are herein reported. A mammalian faunal list is given in Table 1.

Class MammaliaOrder Soricomorpha

Family SoricidaeSorex taylori Hibbard, 1938

Figure 14AReferred specimens. Pit C: 4300, edentulous left dentary. Pit D:

4000-4007, 4122-4130, 27 left dentaries and dentary fragments; 4008-4014, 4131-4136, 23 right dentaries and dentary fragments; 4015, left maxillary, P4-M2; 4016, left maxillary, I3-P4 and an isolated left M1. A minimum of 27 individuals are present in the sample from Pit D.

Description. Hibbard (1938) named and described Sorex taylori based on several dentaries from Rexroad Locality 2, Meade County, Kansas, 235 km (146 miles) northeast of the Red Corral sites. He characterized this shrew as being the size of the Holocene Sorex merriami Dobson and gave the following diagnosis: “Protoconid appressing metaconid in m1; m2 and m3 greater (larger) than in living species. All five cusps are developed in the molars; accessory cusps wanting; cingulum strongly developed; ascending ramus well-developed; coronoid process high and narrow leaving the horizontal ramus at a right angle; m3 nearer to ascending ramus than in living species. ”The length of m1-m3 in the holotype, KU 3906, is 3. 4. Additional jaws were recovered from Rexroad Locality 2 and Locality 3 (Hibbard, 1941c, 1953a). Skinner et al. (1972) further noted that the talonids of m1-m3 are about the same width as the trigonids and that, in young adults, the apex of the crown of the first unicuspid is close to the anterior edge of p4.

The availability of a large sample of Sorex taylori (minimum of 27 individuals from Pit D) provides an opportunity to reexamine and reassess the diagnostic characteristics previously given for the species.

TABLE 1. Mammalian Faunal List (X = Presence of taxon at site)Pit A Pit B Pit C Pit D Loc. 5

Class Mammalia Order Soricomorpha Family Soricidae Sorex taylori Hibbard, 1938 X X Family Talpidae Scalopus (Hesperoscalops) rexroadi (Hibbard, 1941b, c) X X Order Chiroptera Family cf. Molossidae X Order Xenarthra Family Megalonychidae Megalonyx sp. X Family Mylodontidae Paramylodon cf. garbanii Montellano & Carranza, 1986 X X Order Lagomorpha Family Leporidae Hypolagus furlongi Gazin, 1934a X X Hypolagus edensis Frick, 1921 X X Hypolagus gidleyi White, 1987 X Pewelagus dawsonae White, 1984 X Sylvilagus hibbardi White, 1984 X X Pliopentalagus sp. X Order Rodentia Family Sciuridae Marmotini genus and species indet. - large X X Marmotini genus and species indet. - medium X X Marmotini genus and species indet. - small X Family Castoridae Procastoroides sweeti Barbour and Schultz, 1937 X Family Geomyidae Geomys (Nerterogeomys) cf. minor Gidley, 1922 X X Geomys sp. - large X X Family Heteromyidae Prodipodomys cf. idahoensis Hibbard, 1962 X X Perognathus cf. gidleyi Hibbard, 1941b, c X X Perognathus cf. pearlettensis Hibbard, 1941a X Family Cricetidae Peromyscus sp. - large X X Peromyscus spp. - small X X Reithrodontomys cf. rexroadensis Hibbard, 1952a X Onychomys cf. pedroensis Gidley, 1922 X X Bensonomys cf. arizonae (Gidley, 1922) X X Sigmodon minor /medius Gidley, 1922 X X Neotoma (Paraneotoma) cf. fossilis Gidley, 1922 X X Order Carnivora Family Canidae Canis lepophagus Johnston, 1938 X X X Urocyon sp. X Borophagus diversidens Cope, 1892 X X X Family Mustelidae Trigonictis cookii (Gazin, 1934b) X Taxidea sp. X Family Procyonidae Bassariscus sp. X Family Felidae Homotherium sp. X X Miracinonyx studeri (Savage, 1955) X X Felis sp. - small X X X Order Proboscidea Family Gomphotheriidae Stegomastodon mirificus (Leidy, 1858) X Order Perissodactyla Family Equidae Nannippus peninsulatus (Cope, 1885) X X X X X Equus spp. X X X X X Order Artiodactyla Family Tayassuidae Platygonus sp. X X Family Camelidae Camelops sp. X X Hemiauchenia cf. blancoensis (Meade, 1945) X X X X X Family Antilocapridae Capromeryx sp. X X Family Cervidae Genus and species indet. X

8

FIGURE 14. Sorex taylori: A, left dentary with incisor, canine, and p3-m3, 4000, Pit D. cf. Molossidae: B, edentulous left dentary, 4316, Pit C. Scalopus (Hesperoscalops) rexroadi: C, right maxillary with M1-M3, 4307, Pit C; D, left M2, 4017, Pit D; E, right humerus, 4310, Pit C; F, right dentary with m1-m3, 4301, Pit C; G, left dentary with m1-m2, 4302, Pit C.

S. taylori appears to be about the size of the Holocene S. merriami Dobson as proposed by Hibbard (1938). In general, the dentary is light and rather slender – not heavy or robust (Fig. 14A). The coronoid process is high and narrow and perpendicular to the horizontal ramus. The protoconid is closely appressed to the metaconid in m1 of young adult individuals that comprise most of the sample. This condition is not apparent in the few middle to old adult individuals observed. A broad reentrant valley separates the paraconid and the metaconid in m1. Contrary to Skinner et al. (1972), the talonids and trigonids are not of equal width in all of the molars but only in m2 (20 of 24). In m1, the talonid is wider than the trigonid, whereas in m3 the reverse is true. An entoconid is strongly developed on m1 and m2 but is weak on m3. However, the talonid on m3 is not significantly reduced. Cingula are usually present on the lower molars, but their development is variable. The p4 is round and broad. An incisor is preserved in two specimens. In one it is broken, but in the other it is complete and contains two denticles on the occlusal edge. The mental foramen is small and located below or just behind the protoconid of m1. The anterior mandibular foramen is typically small and located below the middle of the ramal fossa. In two specimens it is larger and located below the front and the back, respectively, of the ramal fossa. There is no posterior mandibular foramen on any of the specimens. Length of m1-m3 in Pit D sample: N = 9; OR = 3. 4-3. 7; Mean = 3. 54. Additional tooth and jaw measurements following those used by Jammot (1972) are given in Table 2.

Two M1s and one M2 are present in the sample; a very small

cingulum is present anterior to the protocone on both M1s but is absent on the M2. Eshelman (1975) observed the same condition in a maxillary of Sorex taylori from the Wendell Fox LF of Kansas. By contrast, in S. sandersi, the anterior cingulum is much better developed on M1 and is also present on M2.

Remarks. Several species of Sorex have been described from Blancan faunas but nearly all are known from only a few specimens. Four species from the early Blancan Hagerman LF of Idaho (Hibbard and Bjork, 1971) are easily distinguishable from S. taylori. In S. powersi there is a posterior mandibular foramen that is larger than the anterior one, and both are situated in a deep depression. S. hagermanensis has a heavier and larger jaw and also has a posterior mandibular foramen. S. meltoni is smaller – about the size of S. cinereus – and also has a posterior mandibular foramen. S. rexroadensis, known also from the Fox Canyon LF of Kansas (Hibbard, 1950), is the smallest Blancan shrew. A posterior mandibular foramen is present in the Fox Canyon holotype but not in the Idaho specimens. S. sandersi from the late Blancan Sanders LF (Hibbard, 1956) and White Rock LF (Eshelman, 1975) of Kansas and the Sand Draw LF of Nebraska (Skinner et al., 1972) lacks a posterior mandibular foramen but is slightly larger and has a heavier jaw than S. taylori, and the p4 is less rounded and narrower. Length of m1-m3 in the holotype, UMMP V31976, is 3. 8. S. leahyi from the late Blancan Dixon LF of Kansas (Hibbard, 1956) is also larger than S. taylori and also lacks a posterior mandibular foramen, and the teeth are reported to be slightly narrower. The holotype, UMMP V31969,

9

the two cusps are more closely appressed in m3 than in m1 or m2. The protoconid, entoconid, and hypoconid are well-developed in all three teeth. The anterointernal basal accessory cusp (aibac) is present on all three teeth – widest (0. 9x0. 4) on m3 (about 2/3 the width of the trigonid) but narrower on m1 (0. 8x0. 3) and m2 (0. 8x0. 4). It projects forward about 0. 4 and upward at its anterior edge to enclose a labially sloping groove. The posterointernal basal accessory cusp (pibac) is present on m1 (0. 4x0. 3) and m2 (0. 4x0. 3) but absent on m3. It is narrower than the aibac and overlaps lingually that cusp on the next molar behind. The external median basal accessory cusp (embac) extends forward from the anterior wall of the talonid. This cusp is very prominent on m3 – nearly filling the protoconid-hypoconid valley – but less developed on m2 and weakly developed on m1. All three teeth are two-rooted. Little or no cementum is present. No foramina or processes are preserved. The lingual jaw depth below m2 is 4. 1 and below m3 is 3. 6.

A left dentary fragment, 4302, contains m1-m2 and the alveoli of c, p2-p4 (Fig. 14G). The teeth are less worn than in 4301. The paraconid is closer to the metaconid in m2 than in m1. The aibac is small (0. 4x0. 2) on m1 and very large (0. 8x0. 3) on m2. The pibac is large (0. 5x0. 4) on m1 and broken off on m2. The embac is moderately developed on m2 and very faint on m1. There is cementum in both labial and lingual valleys of both teeth. The jaw is broken across the m3 alveolus. There is a large mental foramen below the p3 alveolus and two small ones below the m1 talonid. The lingual jaw depth below m1 is 3. 4 and below m2 is 3. 7.

A right dentary fragment, 4303, is broken across the m1 alveolus but contains m2 and the alveolus of m3. The m2 shows little wear, and the paraconid does not crowd the metaconid. The aibac and pibac are prominent and the former is only slightly wider (0. 7x0. 4) than the latter (0. 5x0. 4). The embac is moderately developed. The jaw is broken across the base of the ascending ramus and across the angular process. No foramina are preserved. The lingual jaw depth below m2 is 3. 5 and below the m3 alveolus is 3. 1.

A right dentary, 4304, broken across the base of the ascending ramus contains m1 and the alveoli of p3, p4, m2, and m3. The alveolar length of p3-m3 is 10. 4 and that of m1-m3 is 7. 9. The m2 is moderately worn. The aibac is weak, but the pibac is a strongly developed knob

lacks m1. However, m1 is present in the paratype, UMMP V31970, and the length of m1-m3 = 3. 6. S. leahyi is supposedly distinguished by a narrower and distinctly developed posterointernal ramal fossa and by a broad, flattened posterior border on the coronoid process. However, because of the considerable variability of some features in Sorex, additional specimens of both S. sandersi and S. leahyi are needed to further delineate differences and similarities between these two species and S. taylori. Skinner et al. (1972) suggested that S. sandersi may have been derived from S. taylori.

Sorex taylori is currently known or reported from Rexroad Localities 2, 2a, and 3 (Hibbard, 1938, 1941c) and the Borchers LF (Hibbard, 1941a) of Kansas; the Blanco (Dalquest, 1975) and Beck Ranch (Dalquest, 1978) local faunas of Texas; and the California Wash LF of Arizona (Lindsay, 1984; Morgan and White, 2005). Hibbard (1953a) considered the species to be a moist, lowland dweller. This is consistent with its abundance at Pit D and its near absence at Pit C in the Red Corral LF.

Family TalpidaeScalopus (Hesperoscalops) rexroadi (Hibbard, 1941b, c)

Figures 14C-G Referred specimens. Pit C: 4301, right dentary fragment with

m1-m3; 4302, left dentary fragment with p3-p4 alveoli, m1-m2; 4303, right dentary with m2, m3 alveolus; 4304, right dentary with base of the incisor, m1 and the alveoli of p3, p4, m2, and m3; 4305, edentulous right dentary fragment with m3 alveolus; 4306, edentulous left dentary fragment with alveoli for m2 and m3; 4307, right maxillary fragment with M1-M3; 4308, left maxillary fragment with M1-M2; 4309, isolated teeth; 4310, right humerus; 4311-4314, four left humeri; 4315, proximal end of right ulna and parts of four others, six complete and six partial radii, four partial scapulae, and 12 phalanges. Pit D: 4137, left maxillary fragment with M1-M2; 4017, left maxillary fragment with M2; 4018, isolated teeth; 4019, right humerus; 4020, left humerus.

Description. The subgenus Hesperoscalops is characterized by the presence of large basal accessory cusps in the lower molars. WT 4301, a right dentary fragment broken anterior to m1, contains m1-m3 and best illustrates the cusp development in this mole (Fig. 14F). The paraconid is smaller than the metaconid in all three teeth, and

TABLE 2. Measurements (in mm) of Sorex taylori dentaries from Red Corral Pit D. Measurements used follow Jammot (1972). Abbreviations: L = lower jaw measured fromthe ventral angular inflection to the mental foramen. H = height of ascending ramus measured from the ventral angular inflection to the tip of the coronoid process. m1-m3 = greatest occlusal length of lower molars. h1 = lingual jaw depth below entoconid of m1.

left jaws right jawsWT No. L H m1-m3 h1 WT No. L H m1-m3 h1

4000 4.7 brk. 3.5 1.3 4008 NA NA 3. 5 1.24001 4.4 4 3.7 1.3 4009 4.5 4.05 NA 1.34002 4. 4. 1 NA 1.3 4010 NA 3.9 NA NA4003 brk. 3. 65 3. 5 1.3 4011 4. 5 4 NA 1.34004 4.6 brk. NA 1.3 4012 4. 5 3.95 NA 1.24005 NA NA 3.5 1.3 4013 NA 3.95 NA NA4006 NA NA 3.6 1.2 4131 4.5 3.9 NA 1.24122 4.2 3.9 3.6 NA 4132 NA NA NA 1.34123 NA 4.1 NA NA 4133 NA NA 3. 4 1.24124 NA NA NA 1.3 4134 4.5 NA 3. 6 1.34125 NA NA NA 1.15 4135 NA NA NA NA4126 NA NA NA NA 4136 NA NA NA 1.14127 4.5 NA NA 1.35 4014a 4.6 3.95 NA 1.14128 NA NA NA NA 4014b 4.6 3.95 NA 1.24129 NA NA NA 1 4014c NA 4.1 NA NA4130 NA NA NA NA 4014d NA NA NA NA4007a 4.6 NA NA 1. 34007b NA 3. 75 NA NA4007c NA 3. 8 NA NA4007d NA 3. 8 NA NA

N 7 8 6 12 N 7 9 3 11OR 4. 2-4. 7 3. 65-4. 1 3. 5-3. 7 1. 0-1. 35 OR 4.5-4.6 3.9-4.1 3.4-3.6 1.1-1.3

Mean 4. 5 3. 89 3. 57 1. 26 Mean 4.53 3.97 3.5 1.22SD 0. 163 0. 166 0. 082 0. 097 SD 0. 049 0. 067 0.1 0.075

Combined sample (left and right jaws)14 17 9 23 Note: lefts and rights of single individuals may be present in

combined samples. OR 4.2-4.7 3.65-4.1 3. 4-3.7 1.0-1.35

Mean 4.51 3.93 3.54 1.24SD 0.117 0.127 0.088 0.088

10(0. 5x0. 3). The embac is also well-developed. There is a large mental foramen below the p3 alveolus, two smaller ones below the p4 alveolus, and two still smaller ones below m1 and the m2 alveolus respectively. The lingual jaw depth below m1 is 3. 1, below the m2 alveolus is 3. 5, and below the m3 alveolus is 3. 5. Measurements of isolated lower molars as well as those in jaw fragments from Red Corral Pits C and D and Blancan sites in Kansas and elsewhere in the Texas Panhandle are summarized in Table 3.

In an edentulous right dentary fragment, 4305, the lingual jaw depth below the m3 alveolus is 3. 0 and the labial jaw depth is 2. 5. In an edentulous left dentary fragment, 4306, the lingual jaw depth below the m2 alveolus is 3. 8 and below the m3 anterior root alveolus is 3. 7.

A left maxillary fragment, 4308, contains M1-M2. The anteroposterior length of M1-M2 is 5. 4. The crowns of these teeth fit closely together along the labial side in contrast to the widely spaced teeth in modern Scalopus. In both teeth, the protocone is a prominent but low cusp which extends labially as a broad, low shelf between the paracone and metacone. The parastyle is absent in M1, but a slight ridge along the anteroexternal root surface may represent a vestigial parastyle. The parastyle is well-developed in M2. A wide, deep valley

separates the parastyle and mesostyle 1 internally in M2, although the styles touch labially – being separated only by a slit. Valley development is similar between mesostyle 2 and the metastyle in both M1 and M2, although a small cusp blocks this valley labially in M2. Two anterior roots are present on each tooth, but the posterior roots are fused into one long root. The notch between the maxillary and the jugal process ends just opposite the posterior edge of M2, as in S. (H.) rexroadi and modern Scalopus.

Several other tooth-bearing maxillary fragments (Figs. 14C-D) from both Pits C and D were examined. The tooth characteristics of M1 and M2 are like those in 4308. Several isolated M3s are also present in the sample. M3 is smaller than the other molars and lacks a metastyle giving the tooth a rounded posterior margin. Measurements of isolated upper molars as well as those in maxillary fragments are given in Table 3.

Several humeri are present in the sample (Fig. 14E). They are slightly smaller than those of modern Scalopus with which they were compared, and the articular processes appear to be not as well-developed.

TABLE 3. Statistical summary of tooth measurements (in mm) of Scalopus (Hesperoscalops) from Red Corral and other Blancan local faunas. Abbreviations: L = length; Wtri = width of trigonid;Wtal = width of talonid. Red Corral Pit C Red Corral Pit D

Tooth Measure N OR Mean SD Tooth Measure N OR Mean SDm1 L +cusps 3 2. 8-3. 0 2. 9 0. 1 m1 L +cusps 1 2. 6

L -cusps 3 2. 2-2. 5 2. 37 0. 153 L -cusps 1 2. 3Wtri 3 1. 5-1. 8 1. 63 0. 153 Wtri 1 1. 4Wtal 3 1. 8-1. 95 1. 88 0. 076 Wtal 1 1. 8

m2 L +cusps 6 2. 8-2. 9 2. 82 0. 041 m2 L +cusps 1 2. 8L -cusps 3 2. 1-2. 3 2. 23 0. 116 L -cusps 1 2. 1

Wtri 6 1. 7-1. 8 1. 73 0. 052 Wtri 1 1. 6Wtal 6 1. 8-2. 0 1. 91 0. 092 Wtal 1 2

m3 L +cusps 3 2. 1-2. 3 2. 2 0. 1L -cusps NA NA NA NA

Wtri 3 1. 5-1. 6 1. 55 0. 05Wtal 3 1. 3-1. 4 1. 33 0. 058

M1 L 8 2. 2-2. 8 2. 51 0. 164 M1 L 1 2. 5W ant 8 2. 0-2. 3 2. 12 0. 089 W ant 1 2. 2W post 8 1. 7-2. 2 1. 85 0. 16 W post 1 1. 8

M2 L 5 2. 3-2. 6 2. 46 0. 114 M2 L 2 2. 2-2. 5 2. 35W ant 5 2. 1-2. 5 2. 32 0. 148 W ant 2 2. 3-2. 4 2. 35W post 5 1. 6-1. 9 1. 76 0. 114 W post 2 1. 8-1. 9 1. 85

M3 L 5 1. 6-1. 8 1. 74 0. 089 M3 L 1 1. 9W 5 1. 6-1. 8 1. 7 0. 071 W 1 1. 8

Rexroad Locality 3 - S. rexroadi Fox Canyon - S. rexroadiTooth Measure N OR Mean SD Tooth Measure N OR Mean SD

m1 L +cusps 1 2. 8 m1 L +cusps 7 2. 3-2. 9 2. 63 0. 18L -cusps 1 2. 4 L -cusps 7 2. 1-2. 4 2. 29 0. 09

Wtri 1 1. 7 Wtri 7 1. 4-1. 8 1. 54 0. 162Wtal 1 2 Wtal 7 1. 7-2. 0 1. 82 0. 099

m2 L +cusps 2 2. 7 2. 7 m2 L +cusps 5 2. 7-3. 0 2. 82 0. 13L -cusps 2 2. 2-2. 25 2. 22 L -cusps 5 2. 2-2. 3 2. 26 0. 055

Wtri 3 1. 7-2. 1 1. 91 Wtri 6 1. 5-1. 9 1. 73 0. 14Wtal 3 1. 7-2. 3 2 Wtal 6 1. 7-2. 1 1. 88 0. 16


Wtri 2 1. 75-1. 9 1. 82 Wtri 7 1. 3-1. 6 1. 49 0. 122Wtal 2 1. 3-1. 4 1. 35 Wtal 7 1. 05-1. 3 1. 18 0. 099

Rexroad Loc. 2 Type S. rexroadi Type of S. sewardensism2 L 1 3. 2 m2 L +cusps 1 3. 55

W 1 1. 9 L -cusps 1 NAWtri 1 2. 3Wtal 1 2. 5

m3 L 1 2. 6 m3 L +cusps 1 2. 8W 1 1. 6 L -cusps 1 NA

Wtri 1 2. 1Wtal 1 1. 75

11

Remarks. The genus Hesperoscalops was established because of the presence of large basal accessory cusps in the lower molars (Hibbard, 1941b, c). Kurtén and Anderson (1980) noted that similar but smaller cusps are found in some Scalopus, however, and Hesperoscalops is now regarded as a subgenus. Scalopus (Hesperoscalops) rexroadi was described by Hibbard (1941b, c) from Rexroad Locality 2 (early Blancan) of Kansas. This species is also known from other early Blancan faunas including Fox Canyon and Rexroad Locality 3 of Kansas (Hibbard, 1953a) and Beck Ranch of Texas (Dalquest, 1978). It may have given rise to Scalopus aquaticus. S. (H. ) sewardensis is a somewhat larger species described by Reed (1962) from the earliest Blancan Saw Rock Canyon LF of Kansas but it is not considered to be directly ancestral to S. (H. ) rexroadi. S. (H. ) blancoensis from the late Blancan Blanco LF of Texas (Dalquest, 1975) resembles S. (H.) rexroadi but has large, broader teeth and more strongly developed basal accessory cusps, especially on m3 and with m3 more reduced than m2. S. (H. ) mcgrewi described by Voorhies (1977) from the late Hemphillian Santee LF of Nebraska is larger than S. (H. ) sewardensis and S. (H. ) rexroadi (molars at least 20 per cent longer), and cingular cusps are much more prominent with that on m3 forming a distinct shelf approximately as long as the trigonid. Scalopus (Hesperoscalops) sp. is also known from the late Blancan Belen LF of New Mexico (Morgan and Lucas, 2000b).

Order ChiropteraFamily cf. Molossidae

Figure 14BReferred specimen. Pit C: 4316, edentulous left dentary fragment. Description. The dentary fragment (Fig. 14B) is broken just

anterior to the alveolus of m3. The coronoid process and articular condyle are intact. The coronoid process is low and angled somewhat anteriorly; it is reduced more than in North American Pliocene and Pleistocene vespertilionids and about as in molossids (Czaplewski, written communication, 2015). Measurements: anterior end of m3 alveolus to posterior edge of articular condyle = 5. 2; jaw depth below tip of coronoid process = 3. 1; length of m3 alveolus = 1. 1.

Remarks. Fossil bats are rare in Blancan faunas. This dentary was obtained only after screen washing 39 tons of sediment.

Order XenarthraFamily Megalonychidae

Megalonyx sp. Referred specimen. Pit C: F:AM 117198 (formerly F:AM 77811),

a palate with the right first molariform, left caniniform, and alveoli for the remaining upper teeth collected by a Frick party.

Description. The specimen is very fragile and poorly preserved. Some of the tooth alveoli are incompletely surrounded by bone. The brain case is filled with gray sandstone, and what cranial bones remain have been glued back in place and other repairs appear to have been made by the museum staff before processing the loan. No measurements were made by the author.

Hirschfeld and Webb (1968, p. 234-235) give the following description of this specimen: “The widest dimension of the palate is 86. 6 mm across the caniniforms. The palate is constricted posterior to the caniniforms to a width of 37. 2 mm. The width across the posterior molariforms is 58. 0 mm; between them it is 16. 8. The posterior narial opening lies opposite the last molariforms. The caniniform measures 29. 8 mm long by 16. 6 wide and has the lingual convexity characteristic of advanced Megalonyx. M1 measures 17. 2 by 14. 0 mm. The cheek

tooth row is 65. 5 mm long. In anterior view the rostrum presents an elliptical narial opening

with a maximum width of about 38 just dorsal to the palate and narrowing to about 20 between the lateral edges of the nasal bones. The tips of the nasals stand 8 behind the anterior edges of the canines. The anterior edge of the jugal lies immediately posterior to the caniniform. The jugal plate slopes ventrad, posteriad, and slightly laterad. The posterior edge lies posterolateral to M2”.

Remarks. The earliest undoubted occurrence of Megalonyx is in the late Hemphillian at about 6 Ma (Hirschfeld, 1981; Webb and Perrigo, 1985; Morgan, 2008). It likely evolved from the earlier Hemphillian genus Pliometanastes. At any rate, Megalonyx was widely distributed in North America by middle Pliocene time. The Blancan species, M. leptostomus is known from many faunas including several in Texas. It was first described by Cope (1893) based on both premaxillaries, some skull fragments and an upper molariform tooth from the Blanco LF. Additional specimens from the Blanco site were described by Meade (1945) and Dalquest (1975). The species was redescribed by Hirschfeld and Webb (1968) based on more complete material including a skull from the Cita Canyon LF. The palate from Proctor Pit C is inadequate for species identification, however.

Family MylodontidaeParamylodon cf. garbanii Montellano-Ballesteros

and Carranza-Castañeda, 1986Figures 15A-C

Referred specimens. Pit B: F:AM 144640, a left upper fourth molariform tooth. Pit C: F:AM 144641, a left dentary with the second and third molariform teeth and alveoli for the caniniform and first molariform tooth.

Description. The tooth from Pit B (Fig. 15C) is well-preserved and appears to be a left fifth upper tooth (fourth molariform). It is distinctly bilobate with a wider (20. 0) anterior lobe separated from the narrower (11. 2) posterior lobe by a constriction. Greatest length of the tooth is 25. 5. In cross-section, the tooth shows an inner core of vascular dentine surrounded by an outer layer of harder dentine which is, in turn, covered by a thin layer of cementum that is partially peeled away. The maximum tooth height is 57. 9.

The left dentary (Figs. 15A-B) from Pit C is broken anterior to and beneath the caniniform and first molariform alveoli. The alveolar length of the four teeth is 120. 5. The third tooth (second molariform) is rectangular in occlusal outline and has its long axis oblique to the tooth row. It is slightly bilobate with only a slight constriction. Greatest length is 24. 0 and greatest width is 14. 4. The last tooth (third molariform) is elongate. The anterior and posterior lobes are directed medially and are separated by a narrow constriction. AP length = 43. 4; width of anterior lobe = 23. 2; width of posterior lobe = 18. 3. The lingual jaw depth below the third molariform is 69. 5. The labial jaw depth below the second molariform is 65. 8. The jaw width at midsection is 31. 2.

Remarks. The largest and probably best known species of this genus is Paramylodon harlani, found in numerous Pleistocene faunas in North America including Rancho La Brea, California, which contains a large sample of material described by Stock (1925). A smaller mylodontid sloth has been recognized in several late Blancan faunas in Florida, Idaho, and the southwestern United States – usually from a few isolated teeth or a single bone. Akersten (1972) referred two caniniform teeth, a fragmentary edentulous right dentary, and an ungual phalanx from the Red Light LF of Texas to Paramylodon sp. Hager (1974) referred a second upper molariform tooth from the Donnelly

Blanco - S. blancoensis Beck Ranch - S. rexroadiTooth Measure N OR Mean SD Tooth Measure N OR Mean SD


Wtri 1 1. 7 Wtri 5 1. 3-1. 6 1. 42 0. 115Wtal 1 2. 05 Wtal 5 1. 55-1. 9 1. 69 0. 134

m2 L +cusps 2 3. 1-3. 15 3. 12 m2 L +cusps 7 2. 55-2. 9 2. 68 0. 115L -cusps 2 2. 3-2. 6 2. 45 L -cusps 7 2. 0-2. 3 2. 17 0. 111

Wtri 2 1. 6-1. 85 1. 72 Wtri 7 1. 3-1. 7 1. 46 0. 149Wtal 2 1. 8-2. 0 1. 9 Wtal 7 1. 6-1. 9 1. 7 0. 1

m3 L +cusps 3 2. 4-2. 45 2. 42 0. 029 m3 L +cusps 5 2. 0-2. 4 2. 21 0. 143L -cusps 3 2. 0-2. 2 2. 13 0. 116 L -cusps 5 1. 8-1. 9 1. 86 0. 055

Wtri 3 1. 45-1. 8 1. 58 0. 189 Wtri 5 1. 3-1. 5 1. 38 0. 11Wtal 3 1. 2-1. 6 1. 43 0. 208 Wtal 5 1. 15-1. 2 1. 19 0. 022

12Ranch LF of Colorado to the same genus as well. Robertson (1976) described a partial skeleton, including the skull and mandible, of a sloth smaller than P. harlani from the Haile XV A LF in Florida that he assigned to the South American genus and species Glossotherium chapadmalensis. A year earlier, Dalquest (1975) referred nine isolated teeth from the Blanco LF to Glossotherium near chapadmalense on the basis of their similarity to teeth in the then unpublished skeleton from the Haile XVA LF.

McAfee (2009) made a distinction between Pleistocene Glossotherium of South America and Pleistocene Paramylodon of North America based on certain features of the cranium, mandible, and dentition. He considered chapadmalense, originally named and described as a species of Eumylodon by Kraglievich (1925) from the Pliocene of Argentina, to be a member of Glossotherium as had Hoffstetter (1952) and suggested that this species might be close to the ancestry of both Glossotherium and Paramylodon. The consensus among most workers now is that the small mylodont that participated in the Blancan phase of the Great American Biotic Interchange (GABI) gave rise to the larger Paramylodon harlani during the latest Blancan of North America (McDonald, 1995; McAfee, 2009). Morgan (2008) referred this Blancan immigrant, previously identified as Glossotherium or “Glossotherium” chapadmalense to Paramylodon and suggested that the small late Blancan mylodonts from temperate North America might be conspecific with P. garbanii, a small species

originally described from the early Blancan Arroyo El Tanque site in Guanajuato, central Mexico (Montellano-Ballesteros and Carranza-Castañeda, 1986). Authors of recent publications describing mylodont fossils from Blancan faunas in Idaho, Nebraska, California, Arizona, and southwestern New Mexico are divided as to whether the generic assignment should be Glossotherium or Paramylodon. Cassiliano (1999) listed Glossotherium as a component of the late Blancan Vallecito Creek LF in the Anza-Borrego Desert of California whereas Schultz and Stout (1948) listed Paramylodon as a component of the Blancan age Broadwater LF of Nebraska. Some authors have followed Morgan (2008) and referred their fossils to P. cf. garbanii. Notable records from Arizona cited earlier by Morgan and White (2005) and White and Morgan (2005) as Glossotherium are from the 111 Ranch LF in southeastern Arizona (Galusha et al., 1984); and the Pearson Mesa LF along the Arizona-New Mexico border (Morgan and Lucas, 2000a). McDonald and Morgan (2011) summarized the record of Glossotherium (= Paramylodon) from several late Blancan faunas in southwestern New Mexico. These include an ungual phalanx from the Williamsburg LF (Morgan, 2008; Morgan et al., 2011); the distal two-thirds of a left femur from the Pearson Mesa LF (Morgan and Lucas, 2000a; Morgan et al., 2008); and a crushed partial skull with two teeth, a fragment of a distal humerus, a partial right dentary with fragmentary teeth, and a partial left dentary with associated tooth fragments from the La Union LF (Vanderhill, 1986; Morgan and Lucas, 2003; Morgan, 2008). It

FIGURE 15. Paramylodon cf. garbanii: A, dorsal view and B, labial view of left dentary with second and third molariforms, F:AM 144641, Pit C; C, occlusal view of upper fourth molariform, F:AM 14464, Pit B. Scale bar = 2 cm. for all specimens.

13should be noted that McDonald and Morgan (2011) have stated that “detailed comparisons have yet to be made among the various Blancan samples of small mylodonts from temperate North America, including New Mexico, and between these samples and cf. garbanii. ”

The left dentary from Proctor Pit C matches in size and morphology that of the Haile XV A mandible described by Robertson (1976), and the size and shape of the lower second molariform alveolus matches that of the type specimen of Paramylodon garbanii from Mexico. The lower third molariform in the Proctor Pit C dentary also matches in size and morphology a similar tooth figured by Dalquest (1975) from the Blanco LF, assuming that his figure was reproduced at natural size. In addition, the Proctor Ranch dentary matches in size and morphology several undescribed specimens from Bed 2 (= Unit 2) of the Cita Canyon LF of Texas, listed as Paramylodon sp. by Johnston and Savage (1955). Based on these considerations, it seems reasonable to assign the Proctor Ranch specimens to Paramylodon (= Glossotherium) cf. garbanii pending further study and discovery of additional fossils. At any rate, the presence of a small species of Paramylodon (= Glossotherium) in the Red Corral (Proctor Ranch) LF suggests an early late Blancan age (3. 0-2. 6 Ma) for the fauna and a possible correlation with the lower faunal unit of the Cita Canyon LF. Finally, it should be noted that Sankey (2002) referred a partial skeleton from the latest Blancan age Glenns Ferry Formation in Idaho to Paramylodon harlani although she noted that it was smaller than P. harlani from the late Pleistocene American Falls LF of Idaho and the Rancho La Brea Fauna from California. McDonald (written communication, 2016) states that the fossils are latest Blancan but close to the Irvingtonian boundary and might be called Glossotherium chapadmalense/garbanii.

Order LagomorphaFamily Leporidae

Rabbits are represented in the Red Corral LF by a diversity of species if not by an abundance of specimens. The fossils consist of isolated teeth, dentary fragments, and some postcranial material. The teeth were studied and identified by the late John A. White, who made many camera lucida drawings of the occlusal patterns of the diagnostic lower third premolar. Some of these were included in his monumental publications on the Archaeolaginae (White, 1987) and the Leporinae (White, 1991). In the following descriptions, measurements in millimeters of the lower p3s are given using the method illustrated in White (1987, p. 426) for the Archaeolaginae and in White (1991, p. 68) for the Leporinae. Abbreviations used for the following measurements are: anteroposterior length (AP), width (W), depth of anteroexternal reentrant (AER), maximum depth of posteroexternal reentrant (PER), depth of posteroexternal reentrant to point of constriction in leporines (PERc), thick enamel on anterior border of the posteroexternal reentrant (TH), thin enamel on posterior border of the posteroexternal reentrant (TN), anterior reentrant (AR), anterointernal reentrant (AIR), posterointernal reentrant (PIR). See Figure 16A.

Subfamily Archaeolaginae Hypolagus furlongi Gazin, 1934a

Figures 16B-IReferred specimen. Pit C: 4463, right dentary fragment with p3-

m1; 4464, left dentary fragment with p3-m3; 4467, complete left lower dentition; 4477, three left and two right p3s. Pit D: 4093a, left p3.

Description. A right dentary fragment, 4463, contains p3-m1 and a broken incisor 3. 5 wide. The p3 of this specimen is shown as Figure 16B. The minimum diastema length is 13. 3. The mental foramen is large with broken edges and is dorsolabially placed. Its posterior border is 1. 3 anterior to the p3 alveolus. Lingual jaw depth ahead of p3 = 9. 1. The left dentary fragment, 4464, of a small individual is broken anterior to p3 and posterior to m3. The p3 of this specimen is shown as Figure 16C. The left p3, 4093a (Fig. 16I), from Pit D resembles those from Pit C. Measurements of the p3s are given in Table 4. In all of the p3s, the PER is straight and directed inward nearly perpendicular to the AP line. TH is straight to slightly wavy and extends the entire PER distance but may show slight inward thinning in some cases. The AER: W ratio ranges from 19 to 32 % (N = 9, mean = 25. 0 %. The PER: W ratio ranges from 45 to 57 % (N = 9, mean = 52. 7 %).

Remarks. The holotype described by Gazin (1934a) is a right dentary with i-m2 from the late Blancan Grand View LF of Idaho. White (1987, p. 436) gave an emended diagnosis of the species and comparisons with other species of the genus and noted that it is comparable in size to Hypolagus edensis but differs from it in having a significantly shallower AER. He figured several p3s on page 433

including 4477b (fig. 7, N3) for which he gave an old catalog number (WTSU 4468g). The correct new number is listed in his list of referred specimens, however. New numbers were later assigned when it became clear that p3s of several species had been lumped under one catalog number. Hypolagus furlongi is now recognized in Blancan faunas from California, Idaho, Nebraska, and Texas (White, 1987, p. 436).

Hypolagus edensis Frick, 1921Figures 16J-M

Referred specimens. Pit C: 4465, left dentary fragment with incisor and p3-p4; 4478a, right p3 and 4478b, left p3. Pit D: 4094, right p3.

Description. Hypolagus edensis is comparable in size to H. furlongi. Both species are smaller than H. gidleyi. A left dentary fragment, 4465, is broken posterior to p4. The p3 of this specimen is shown as Figure 16J. The incisor width is 2. 0. The minimum diastema length is 11. 2. The mental foramen is large (3. 1 long and 1. 5 wide) and dorsolabially placed. Its posterior border is about 0. 6 anterior to the p3 alveolus. The lingual jaw depth ahead of p3 is about 8. 0. Measurements of the p3s are given in Table 4. The AER is broadly V-shaped and terminates in a narrow, rounded U-shaped tip in the two teeth in which it can clearly be seen. It appears to be longer than in those of H. furlongi, which is in agreement with White (1987, p. 437; White and Morgan, 1995, p. 366) in his emended diagnosis (see below). The AER: W ratio ranges from 26 to 45 % (N = 4, mean = 32. 2 %). The PER: W ratio ranges from 50 to 52 % (N = 4, mean = 51. 0 %).

Remarks. The holotype of Hypolagus edensis is a fragmentary dentary with p3-m1 of an immature individual from the Mount Eden LF (Hemphillian) of California (Frick, 1921). White (1987, p. 437) gave an emended diagnosis of the species by stating that “H. edensis is distinguishable from all other species of Hypolagus by the presence of a deep and smooth-sided AER on p3. ” He later added that the species is “distinguishable from all other species of Hypolagus by the presence on p3 of an AER that extends across 25 per cent (N =56) or more of the width of the tooth, and whose innermost portion is symmetrically U-shaped” (White and Morgan, 1995, p. 366). In his 1987 paper, White figured several p3s on page 433 (fig. 7) but none from Red Corral. However, in his list of referred specimens on page 437, WTSU 4468e and 4478f are the old catalog numbers that should be replaced by 4478a and 4478b, respectively. Hypolagus edensis is now recognized from the Hemphillian of Arizona and California and the Blancan of California, Idaho, Nevada, Texas, and Washington (White, 1987, p. 437).

Hypolagus gidleyi White, 1987Figure 16N

Referred specimens. Pit C: 4468a, b, c, and d, four left p3s. Description. The teeth are large. Near the top of 4468a (Fig. 16N),

the enamel has been eroded so that measurements were made at the base of the tooth. Measurements of the p3s are given in Table 4. AER is not as deeply incised as in Hypolagus edensis. The AER: W ratio ranges from 15 to 25 % (N = 4, mean = 18. 0 %). PER is straight and deeply incised with no deflection at its inward end. The PER: W ratio varies from 48 to 75 % (N = 4, mean = 59. 0 %).

Remarks. The holotype of Hypolagus gidleyi is a complete skull of an immature individual from the embayment south of the Horse Quarry, Hagerman LF (Blancan) of Idaho. White (1987, p. 434) compared H. gidleyi with other species of Hypolagus. He noted that “H. gidleyi differs from H. edensis in a markedly less well incised AER and markedly larger size. From H. furlongi it differs in its markedly larger size”. He figured one p3 from Red Corral, correctly numbered as WTSU 4468b, on page 433 (fig. 7, C3) of his 1987 paper. White (1987, p. 434) stated that Hypolagus gidleyi is now recognized from the “Hemphillian of Texas and New Mexico, Blancan of Idaho, Nebraska, Texas, and Washington. ”The Texas Hemphillian record is Coffee Ranch which White in the previous paragraph erroneously listed as Blancan. The Nebraska record is from Oshkosh which is Hemphillian and not Blancan as White stated. The New Mexico specimen is Blancan and is from the Albuquerque Basin and not from the Clarendonian-Hemphillian age Chamita Formation which is restricted to the Espanola Basin of north-central New Mexico– see discussion in Lucas and Williamson (1993, p. 6). H. gidleyi is also recognized from the early Blancan Panaca LF of Nevada (Mou, 2011b).

Hypolagus is represented in the Red Corral LF by three species: a large species, H. gidleyi, and two smaller species, H. furlongi and H. edensis. Some workers might argue that only one small species existed in the Red Corral LF and that H. furlongi and H. edensis are

14

FIGURE 16. Rabbit lower p3s. Pit C unless otherwise stated. Figures are from camera lucida drawings made by John A. White here magnified 24. 6 to 28 times. Actual tooth measurements are given in the text and Table 4. A, Terminology used in text: AR = anterior reentrant; AER = anterior external reentrant; PER = posterior external reentrant; AIR = anterior internal reentrant; PIR = posterior internal reentrant; TH = thick enamel; TN = thin enamel; not shown: PERc = length of PER to point of constriction. Hypolagus furlongi: B, right, 4463; C, left, 4464; D, left, 4477a (formerly 4468d); E, left, 4477b (formerly 4468g); F, left, 4477c (formerly 4468i); G, right, 4477d (formerly 4468c); H, right, 4477e (formerly 4468h); I, left, 4093a, Pit D. Hypolagus edensis: J, left, 4465; K, right, 4478a (formerly 4468c); L, left, 4478b (formerly 4468f); M, right, 4094, Pit D. Hypolagus gidleyi: N, left, 4468b. Pewelagus dawsonae: O, left, 4476 (formerly 4468a). Sylvilagus hibbardi: P, right, 4475a (formerly 4468n); Q, right, 4092, Pit D.

conspecific. It would seem more likely that the two species are distinct and that one of them may have been misidentified in the Red Corral sample. White (1987) recognized 12 species of Hypolagus in the Late Tertiary radiation and proliferation of the genus. In addition to p3 patterns, P2 patterns, and characters of the skull, when available, were used to separate species. In many faunas two, three, or even four species of Hypolagus have been recognized e. g. H. gidleyi, H. furlongi, H. edensis, and H. voorhiesi are recognized from the Blancan age Nine Foot Rapids LF of Idaho (White, 1987) and Mou (2011b) reported H. edensis, H. tedfordi, H. cf. ringoldensis, H. gidleyi, and H. regalis from the early Blancan Panaca LF of Nevada. Future studies may warrant the synonymizing of some species but such a venture is beyond the scope of this paper.

Pewelagus dawsonae White, 1984Figure 16O

Referred specimen. Pit C: 4476, left p3. Description. Measurements of the p3 (Fig. 16O) are given in

Table 4. The AER: W ratio is 27. 3 % and the PER: W ratio is 46. 0 %. PER is mostly straight but shows a very slight posterior deflection of the tip of TH.

Remarks. The holotype of this species and the genus is a cranium from the Arroyo Seco LF (Blancan) in Anza-Borrego Desert State Park, San Diego County, California, which White (1984) stated was near the size of Sylvilagus bachmani. White (1984, p. 47; 1987, p. 441-442) referred several dentaries and lower teeth. In his 1987 paper, he

15

included the Red Corral tooth for which he used the old catalog number, WTSU 4468a (the new correct number is 4476), but did not figure the specimen. In his 1984 paper, he compared the genus and species with species of Hypolagus. He noted that the p3 is small and that “crenulations in the anteroexternal reentrant sets Pewelagus dawsonae apart from Hypolagus furlongi” and that “the p3 in H. edensis Frick (1921) has a size and pattern comparable to that in P. dawsonae and may be referable to this genus” (p. 50). In his 1987 paper, however, he maintained the integrity of both taxa. White (1984, p. 53) stated that “the structure of the cranium in P. dawsoni suggests an erect posture similar to that in Sylvilagus and Brachylagus……based on a pistol grip-like flexion of the posterior end of the cranium.” He went on to say (p. 54-55) that “the flexion of the posterior end of the cranium, the greatly enlarged tympanic bullae, and narrow choanae suggest that P. dawsonae lived in burrows and escaped snakes and owls in a manner similar to Dipodomys (Webster, 1962).” Pewelagus dawsonae is now recognized in the Blancan of California, Nevada, and Texas (White, 1987, p. 443).

Subfamily LeporinaeSylvilagus hibbardi White, 1984

Figures 16P-Q; 17AReferred specimens. Pit C: 4466, left dentary fragment with p3-

p4; 4475, four p3s; 4469, immature, unworn left p3. Pit D: 4092, right dentary with incisor and p3-m2; 4177, four left and five right p3s; 4199, left dentary fragment with p3-m1.

Description. The most complete specimen from Pit C is a left dentary fragment, 4466, which contains p3-p4 and very weathered dentine. No AIR or PIR is present on the p3. The AER: W ratio is 28. 6 %. The PER: W ratio is 64. 3 %. The PER enamel is crenulated and PER becomes constricted at 1. 0 depth (PERc) but then expands and is deflected anteriorly for the remainder of its depth (the “pro-Sylvilagus” pattern of Hibbard, 1963). The PERc: PER ratio is 1. 0:1. 8 or 55. 6 %. No isolated enamel lake or island is present on any of the p3s examined; the tooth morphology is very similar in the other p3s. In the single right p3, 4475a, the AER: W ratio is 18. 5 %, the PER: W ratio is 74. 1 % and the PERc: PER ratio is 60. 0 %. Measurements of the p3 of 4466

and 4475a (Fig. 16P) are given in Table 4. Three broken p3s were not measured. The immature p3, 4469, was not measured but shows slight development of AR, AIR, and PIR.

The most complete specimen from Pit D, 4092, is a right dentary with i, p3-m2. The p3 is shown in Figure 16Q and the dentary in Figure 17A. The incisor width = 2. 6. The diastema is approximately 9. 0. The mental foramen is smaller than in Hypolagus (1. 3 long and 0. 8 wide) and is more laterally placed. Its posterior border is about 1. 8 anterior to the p3 alveolus. Lingual jaw depth ahead of p3 is 8. 5. Measurements of the p3 (Fig. 16Q) are given in Table 4. There is a slight, crenulated AR. The AER: W ratio is 28. 0 %, the PER: W ratio is 72. 0 %, and the PERc:PER ratio is 61. 1%.

A left dentary fragment, 4199, contains p3-m1. On the p3, AR is slightly developed. The AER: W ratio is 22. 7 %, PER: W is 72. 7 %, and PERc: PER is 50. 0 %. A slight crenulated AR is preserved on three other teeth. Measurements of the p3s are given in Table 4.

For the entire sample, the AER: W ratio ranges from 14. 3 to 28. 6 % (N = 8, mean = 21. 8 %), PER: W ranges from 64. 3 to 74. 1 % (N = 7, mean = 69. 9 %), and PERc: PER ranges from 50. 0 to 66. 7 % (N = 7, mean = 58. 8 %).

Some of the upper P2s from Pit D contain three anterior reentrants and probably belong to Sylvilagus hibbardi, whereas others from both pits have a deep main anterior reentrant (MAR) and a shallow external anterior reentrant (EAR) and probably belong to Hypolagus.

Remarks. The holotype of this species is a left dentary fragment with p3-m3 from the Vallecito Creek LF (late Blancan to Irvingtonian), Anza-Borrego Desert State Park, San Diego County, California (White, 1984). White (1984, 1991) referred many dentary fragments to this species. In his 1991 paper he listed all of the Red Corral specimens with currently correct catalog numbers but did not designate from which locality the specimens were taken. It should be noted, however, that in his figure 9, D4 on page 77, specimen 4092 is reversed and is incorrectly given the number 4091 in the figure caption but the correct number, 4092, is used in the text. It should be noted also that the specimens from Cita Canyon listed as WTSU 4500a and 4500b have been assigned new catalog numbers, which are 4623 and 4624. White (1984) reported that 57 % of his sample of p3s showed the ”pro-Sylvilagus” pattern in which the PER joins through a constriction, which, in later Sylvilagus and Lepus would be an enamel island or lake. Sylvilagus hibbardi is now recognized from the Blancan of Arizona, California, and Texas and the Irvingtonian of California, Texas, and Sonora, Mexico.

Pliopentalagus sp. Figures 17B-D

Referred specimens. Pit D: 4095a, right p3; 4095b, left p3; and 4095c, left p3.

Description. Three lower p3s possess five reentrants and are here assigned to the genus Pliopentalagus. The reentrants are filled with cementum. In 4095a and 4095b (Figs. 17B-C), the AR is shallow but broad with three crenulations (folds) in the former and two in the latter. In 4095c (Fig. 17D), the AR is narrower but deeper and has two crenulations. The AIR is small and uncrenulated in all three teeth. In 4095c, it is 0. 2 deep. The AER in 4095a is wide with 3 very shallow crenulations and a narrow, deeper one that extends about two-fifths of the way across the tooth. In 4095b, the AER is narrow and deep and in 4095c it is externally wider with a central, narrow, deep fold. The PIR in 4095a is externally wide with a central fold that extends nearly one-third of the way across the tooth. In 4095b the PIR is externally narrower but broadens to a fold that extends over one-third of the way across the tooth. In 4095c, a pedomorphic form, the PIR is narrow and connects with the PER about half way across the tooth. In 4095a, the PER is externally broad but narrows medially to extend three-fifths of the way across the tooth where it divides into two folds which are narrowly separated from the PIR. In 4095b, the PER divides into two folds, the anterior of which extends over half way across the tooth where it is narrowly separated from the PIR. In 4095c, the pedomorphic form (Fig. 17D), the PER is somewhat crenulated and joins the PIR about half way across the tooth. In 4095a and 4095b, the enamel is very thick on the posterior external surface of the tooth and on the anterior surface of PER as well as on the exterior surface between AR and AER. In 4095c, very thick enamel is present on the anterior surface of the conjoined PER and PIR as well as across the posterior surface of the tooth. Length and width of the teeth are 3. 7 and 3. 0 in 4095a; 3. 3 and 2. 7 in 4095b; 3. 3 and 2. 5 in 4095c.

Remarks. According to Tomida and Jin (2002), the genus Pliopentalagus is ancestral to the living genus Pentalagus. Fejfar

TABLE 4. Measurements (in mm) of rabbit p3s from Red Corral sites. Abbreviations are explained in text and figure 16.

AP W AER AER/W PER PER/W PERc PERc/PERH. furlongi4463 2. 6 2. 2 0. 6 27. 30% 1. 1 50%4464 2. 1 2 0. 4 20% 0. 9 45%4467 2. 1 1. 8 0. 4 22% 1 55. 60%4477a 2. 4 2. 2 0. 6 27. 30% 1. 1 50%4477b 2. 4 2. 1 0. 5 24% 1. 2 57%4477c 2. 1 1. 9 0. 4 21% 1 52. 60%4477d 2 1. 9 0. 6 32% 1 53%4477e 2. 5 2. 1 0. 4 19% 1. 2 57%4093a 2. 4 2. 2 0. 7 32% 1. 2 54. 50%Mean 2. 3 2 0. 6 24. 96% 1. 1 52. 70%H. edensis4465 2. 5 2. 2 0. 6 27. 30% 1. 1 50. 00%4478a 2. 7 2.3 0. 6 26. 00% 1. 2 52. 00%4478b 2. 6 2. 3 0. 7 30. 40% 1. 2 52. 00%4094 2. 3 2 0. 9 45. 00% 1 50. 00%Mean 2. 5 2. 2 0. 7 32. 18% 1. 2 51. 00%H. gidleyi4468a 3. 2 3. 1 0. 5 16. 00% 1. 5 48. 00%4468b 3. 2 3. 1 0. 5 16. 00% 1. 7 55. 00%4468c 2. 7 2. 4 0. 6 25. 00% 1. 8 75. 00%4468d 3. 1 2. 6 0. 4 15. 40% 1. 5 58. 00%Mean 3 2. 8 0. 5 18. 00% 1. 6 59. 00%P. dawsonae4476 2. 5 2. 2 0. 6 27. 30% 1 46. 00%S. hibbardi4466 3. 2 2. 8 0. 8 28. 60% 1. 8 64. 30% 1 55. 60%4475a 3 2. 7 0. 5 18. 50% 2 74. 10% 1. 2 60. 00%4092 3. 2 2. 5 0. 7 28. 00% 1. 8 72. 00% 1. 1 61. 10%4199 2. 2 2. 2 0. 5 22. 70% 1. 6 72. 70% 0. 8 50. 00%4177a 2. 9 2. 3 0. 6 26. 10% 1. 7 73. 90% 1. 1 64. 70%4177b 3 2. 8 0. 4 14. 30% 1. 8 64. 30% 1. 2 66. 70%4177c 3 2. 7 0. 5 18. 50%4177d 2. 4 2. 2 0. 4 18. 20% 1. 5 68. 20% 0. 8 53. 30%Mean 2. 9 2. 5 0. 6 21. 79% 1. 7 69. 93% 1 58. 77%

16(1961) described Alilepus dietrichi from Slovakia (= Slovak Socialist Republic) based on several isolated teeth. Later, Gureev (1964) gave the generic name Pliopentalagus to a new species from Moldavia (based also on a few isolated teeth), as well as to Alilepus dietrichi. Although a few additional fossils were added from a few isolated localities in China, fossil material of Pliopentalagus remained very limited until a discovery in Huainan, Anhui Province, China by Tomida and Jin (2002). This discovery includes not only teeth but also a number of skulls, jaws, and postcranial bones that range in age from latest Miocene (about 6 Ma) to late Pliocene (about 3 Ma), thus making it possible to trace the morphological changes of the Pliopentalagus-Pentalagus lineage for about the last 6 million years. There is a progressive increase in complexity of the reentrant folds through time. It is also possible to consider the relationships of other genera possessing p3s with all five reentrant angles such as Pronolagus, Aztlanolagus, and Trischizolagus to the genus Pliopentalagus. The three p3s from the Red Corral LF most closely resemble illustrations of Pliopentalagus dajushanensis and P. anhuiensis described by Tomida and Jin (2009). These were listed earlier as P. spp. B and C from the early and late Pliocene of China, respectively (Tomida and Jin, 2002, p. 105). However, because of the variation in complexity of the reentrant folds, I am reluctant to assign a species name to these specimens. The Red Corral teeth may well represent the first known Pliocene (Blancan) occurrence of this genus in North America unless a single right p3 from the 111 Ranch LF, Arizona, described as Aztlanolagus agilis (Downey, 1962; Tomida, 1987), turns out to be assignable to Pliopentalagus.

Order RodentiaFamily SciuridaeTribe Marmotini

Genus and species indet. - largeFigures 18E-F

Referred specimens. Pit C: 4317, left lower dentary fragment, p4-m1; 4318, isolated teeth. Pit D: 4021, isolated teeth.

Description. Ground squirrels are represented in the Red Corral LF almost entirely by isolated teeth that fall into three distinct size categories and represent at least three species. A large species is represented by a lower dentary fragment and several teeth in different wear stages. The teeth are the size of those of a small individual of

“Spermophilus” rexroadensis (Hibbard) from Rexroad Locality 3 (Hibbard, 1941b, c; Hazard, 1961) or the Quaternary Otospermophilus variegatus (Erxleben).

In the dentary fragment, 4317, p4 is 2. 7 long and 2. 7 wide (Fig. 18E). The protolophid is absent. The protoconid and metaconid are subequal in size and separated by a notch. The metaconid is slightly higher than the protoconid. The m1 is 2. 6 long and 3. 1 wide and is parallelogram-shaped in occlusal view.

In unworn first and second upper molars, the metaconule (metaloph) does not join the protocone but is separated from it by a sulcus. Mesostyles are present or absent. The parastyle does not bend sharply to join the protocone, and the occlusal outline of the teeth is broadly triangular. These characters suggest that they may belong to the genus Otospermophilus. There are four M3s in the sample. In one, there is a fully developed metaloph extending from the protocone to the labial edge of the tooth; in two others, there is a low metaconule cusp, and, in the fourth, the metaconule and metaloph are absent. The posterior cingulum of M3 does not bend sharply posteriad. In the lower molars, the metaconid is larger and slightly higher than the protoconid and is separated from it by a notch (Fig. 18F). No P3s are present.

Remarks. A number of ground squirrels assigned to Spermophilus (sensu lato) of different sizes have been described from Blancan faunas in the United States on the basis of lower jaws and upper dentitions. Detailed identification of isolated fossil ground squirrel teeth is nearly impossible, and is made more difficult by the recent recognition as numerous genera (Helgen et al., 2009) of species that were once assigned to the genus Spermophilus. Assignment of even complete dentitions to one of the extant generic groups is difficult and probably unwise considering the generalized nature of the fossils. Some of the described characters occur in more than one genus.

Tribe MarmotiniGenus and species indet. - medium

Figure 18GReferred specimens. Pit C: 4319, isolated teeth. Pit D: 4022,

isolated teeth. Description. A medium-sized ground squirrel is represented by

teeth that are narrower transversely than those of Urocitellus richardsonii (Sabine) and Poliocitellus franklinii (Sabine) but larger than those of

FIGURE 17. Sylvilagus hibbardi: A, right dentary with incisor, p3-m2, 4092, Pit D. Pliopentalagus sp. : B, right p3, 4095a; C, left p3,. 4095b; D, left p3, 4095c; - all from Pit D. Figures of the Pliopentalagus p3s are from camera lucida drawings made by John A. White here magnified 25 to 26 times. Actual tooth measurements are given in the text.

17

FIGURE 18. Procastoroides sweeti: A, right DP4, 4032, Pit D; B, 3 immature teeth, 4032, Pit D; C, right M1 or M2, 4023, Pit D; D, upper right and left dentitions, 4027, Pit D. Ground squirrel (large): E, left dentary fragment, p4-m1, 4317, Pit C; F, right lower tooth, 4021, Pit D. Ground squirrel (medium): G, right lower tooth, 4022, Pit D. Geomys (Nerterogeomys) cf. minor: H, right dentary with incisor, p4-m1, 4324, Pit C; I, left dentary with incisor, p4-m3, 4321, Pit C.

Ictidomys tridecemlineatus (Mitchill) and Xerospermophilus spilosoma (Bennett) (Fig. 18G). The teeth are equal in size or slightly larger than those of “Spermophilus” howelli (Hibbard) from Rexroad Locality 3 (Hibbard, 1941b, c). In slightly worn P4, M1, and M2, the metaloph is either separate from the protocone or joins it weakly. Mesostyles are generally absent. The parastyle does not bend sharply to join the protocone, and the teeth are broadly triangular in occlusal view. In M3,

the metaloph (and metaconule) are absent, and a shallow basin occurs behind the protoloph. The posterior cingulum does not bend sharply posteriad.

Tribe MarmotiniGenus and species indet. – small

Referred specimens. Pit C: 4320, isolated teeth.

18Description. At least one species of small ground squirrel is present

in Pit C. The teeth are similar in length but narrower transversely than those of Ictidomys tridecemlineatus. The upper molars are triangular in occlusal outline with narrow to broad V-shaped trigons. In most, the parastyle bends sharply to join the protocone although in a few teeth, the parastyle is less prominent and merges without change of direction. Mesostyles are generally absent, and the metaloph (metaconule) is separated from the protocone by a sulcus. The lower molars are rhomboidal in shape in occlusal view.

Remarks. The presence of more than one species of ground squirrel is not uncommon in Blancan faunas; frequently, a large and a small species occur together.

Family CastoridaeProcastoroides sweeti Barbour and Schultz, 1937

Figures 18A-DReferred specimens. Pit D: 4023, right M1 or M2; 4024, right

M3; 4025, right M1 or M2; F:AM 65208, right M1 or M2; 4138, right m1 or m2; UMMP 42632, right m1 or m2; 4032, deciduous premolars and immature molars; 4026, incisor fragments; 4027, skull fragments including upper dentitions and an associated atlas; 4028, right astragalus; 4029, phalanges; 4030, caudal vertebra; 4031, patella; UCMP 43406, distal right humerus.

Description. Terminology used in tooth descriptions is that of Stirton (1935), Shotwell (1955), and Woodburne (1961). A slightly modified terminology was used by Martin (2014) for Dipoides in which he replaced the names of lophs (-ids) with numbers. Lophs were numbered consecutively from 1 (anterior) to 4 (posterior) on each upper cheek tooth and lophids were numbered consecutively from 1 (posterior) to 4 (anterior) on each lower cheek tooth. Loph 4 and lophid 4 are best seen on P4 and p4 respectively. Mature molars usually display 3 lophs and 3 lophids (1, 2, and 3). This system is here applied to Procastoroides and Martin’s numbers are given in parentheses following the loph (-id) name for the sake of future comparisons.

WT 4023 is a right M1 or M2 (Fig. 18C). The anterior loph (1) is uninflated and moderately crescentic with the convex side anterior. The median loph (2) is slightly inflated anteriorly with the posterior enamel wall nearly straight. The posterior loph (3) is inflated labially. The hypoflexus terminates flat against a thin labial enamel wall but interrupts the wall about 3. 5 below the occlusal surface to create a pseudohypostria. The mesoflexus trends posterolingually and interrupts the lingual enamel wall about 0. 3 below the occlusal surface to create a pseudomesostria. The hypostria and mesostria are present and persist to the base of the tooth. The AP tooth thickness is 7. 7; AP L is 8. 9; and TW is 8. 9.

WT 4024 is a right M3. The anterior loph (1) is slightly inflated anteriorly with the labial end inflected posteriorly. The median loph (2) and the first posterior loph (3) are uninflated and crescentic with the convex side anterior. The second posterior loph (4) is oval-shaped and broken near the occlusal surface. The hypoflexus terminates as a slightly rounded enamel loop but interrupts the labial enamel tooth wall about 0. 8 below the occlusal surface to form a pseudohypostria. In the mesoflexus, the enamel termination wall is flat and abuts the lingual enamel wall of the tooth. In the metaflexus, the enamel termination wall is rounded and slightly separated from the lingual enamel wall of the tooth. The hypostria, mesostria, and metastria are present and persist to the base of the tooth. The AP tooth thickness is 8. 8; AP L is 9. 5; and TW is 8. 5.

WT 4025 is a right M1 or M2. The lophs are uninflated. The anterior loph (1) is crescentic with the convex side anterior; the median loph (2) is straight; and the posterior loph (3) is slightly crescentic with the concave side anterior. The enamel termination of the hypoflexus is nearly flat, and there is no pseudohypostria. The mesoflexus trends posterolingually and interrupts the lingual tooth wall to form a pseudomesostria. The hypostria and mesostria are present and persist to the base of the tooth. The AP tooth thickness is 8. 9; AP L is 9. 7; and TW is 11. 3.

F:AM 65208 is a right M1 or M2. The anterior loph (1) is very slightly inflated lingually and slightly crescentic with the convex side anterior. The median loph (2) is uninflated with the walls slightly crescentic. The anterior wall of the posterior loph (3) is straight, whereas the posterior wall is convex posteriorly. The hypoflexus terminates flat against a thin labial enamel wall but interrupts the wall about 1. 4 below the occlusal surface to create a pseudohypostria. The mesoflexus trends posterolingually and terminates flatly against the lingual enamel wall. A pseudomesostria is not developed. The hypostria and mesostria are

present and persist to the base of the tooth. The AP tooth thickness is 9. 0; AP L is 10. 0; and TW is 9. 5.

WT 4138 is a right m1 or m2. The occlusal pattern is S-shaped. The anterior lophid (3) is crescentic with the convex side anterior and is inflated lingually. The median lophid (2) is straight, uninflated, and trends anterolabially. The posterior lophid (1) is slightly inflated labially and trends anterolabially. The mesoflexid trends anteriorly, and its termination is broken. The hypoflexid trends posterolingually and its enamel termination is slightly rounded. There are no pseudostriids. The mesostriid and hypostriid are present and persist to the base of the tooth. The AP tooth thickness is 8. 9; AP L is 10. 0; and TW is 10. 4.

UMMP 42632 is a weathered right m1 or m2. The occlusal pattern is S-shaped. The anterior lophid (3) is slightly crescentic with the convex side anterior and is inflated lingually. The median lophid (2) is straight, uninflated and trends anterolabially. The posterior lophid (1) is slightly inflated and trends anterolabially. The mesoflexid trends anterolabially and terminates labially at the tooth wall to produce a pseudomesostriid. The hypoflexid trends posterolingually and terminates lingually at the tooth wall to produce a pseudohypostriid. The mesostriid and hypostriid are present and persist to the base of the tooth. The AP tooth thickness is 9. 3; AP L is 10. 0; and TW is 10. 2.

Among the isolated teeth, 4032, are several immature molars and deciduous premolars (Figs. 18A-B). In two lower left m1s or m2s, the anterior lophid (4-3) is partially divided lingually by a shallow paraflexid, and the parastriid extends only to a depth of about 2. 0 below the occlusal surface. The hypoflexid is deep and narrow, and there is a small hypofossetid situated within the dentine between the termination of the hypoflexid and the lingual tooth wall.

There are two well-worn right DP4s almost completely surrounded by enamel. In the less worn of these, a narrow paraflexus extends nearly half way across the tooth and is inflected anteriorly near its termination. A broad, well-developed hypoflexus extends over half way across the tooth nearly meeting the paraflexus and leaving only a narrow connection between the anterior (1) and median (2) lophs. A narrow mesoflexus extends nearly across the entire tooth and is inflected posterolingually at its mid-point. The posterior loph (3-4) is oval-shaped and contains a small metafossette indicating the probable presence of a metaflexus in earlier wear. The tooth has a large medial root and two small labial roots.

There are four dp4s (three rights and one left). The occlusal pattern is basically S-shaped with well-developed mesoflexids and hypoflexids. In one tooth, a shallow paraflexid extends about half way across the tooth to partially divide the anterior lophid. In another, the paraflexid extends entirely across the tooth to isolate an oval-shaped first anterior lophid from the second anterior lophid, which opens broadly into the median lophid. In the latter tooth the termination of the hypoflexid is pinched off to isolate a small fossettid near the connection between the median and posterior lophids. All dp4s possess two roots – one anterior and one posterior.

WT 4026 consists of several incisor fragments, the largest being a part of a curved upper incisor that has a maximum width of 15. 5. The anterior surface is rounded and smooth and lacks any longitudinal grooves.

The skull fragments, 4027, are badly weathered and cannot be easily reassembled. They include parts of the skull roof, zygomatic arches, and palate. Cheek teeth present include left and right M1-M3, but they are too weathered to provide useful measurements and there is unequal wear between the left and right teeth (Fig. 18D). Associated with the skull are the atlas vertebra and a thoracic vertebra.

Other postcranial material includes the distal end of a right humerus, UCMP 43406, in which the ulnar facet is 24. 6 wide. A patella, 4031, measures 28. 3 by 22. 2. Measurements of a modern Castor patella are 21. 2 by 16. 0. A right astragalus, 4028, has a maximum AP L of 28. 1 and is 27. 6 wide. It is larger than that of a modern Castor (AP L = 24. 0; TW = 22. 5) but smaller than two right astragali, UMMP 57400 (AP L= 34. 6) and UMMP 57401 (AP L = 32. 0 and TW = 31. 5) from the Sand Draw LF. of Nebraska (Skinner et al., 1972). An unnumbered right navicular is 25. 2 wide. Also present are several isolated metatarsals and phalanges and a caudal vertebra.

Remarks. Procastoroides is a genus of beavers of large body size, most of which were about two-thirds the size of species of Castoroides. Procastoroides is known from the Blancan of North America, where three species are recognized (Xu, 1995; Korth, 2002). P. sweeti is a Great Plains species that was first described by Barbour and Schultz (1937) from the Broadwater LF of Nebraska. It is also known from the Sand Draw and Mullen I local faunas of Nebraska, the Delmont

19LF of South Dakota (Martin and Harksen, 1974), and the Rexroad Locality 3, Deer Park, Dixon, and White Rock local faunas of Kansas in addition to the Red Corral LF of Texas (Kurtén and Anderson, 1980). The genus is also represented by undescribed teeth from the Bivins Pit 2 LF site located 11 km (7 miles) south of Channing in Oldham County, Texas (R. Tedford, written communication, 1986). Eocastoroides lanei Hibbard from Deer Park and Rexroad Locality 3 is a synonym (Hibbard, 1938). A distinguishing character is the absence of crenulations on the enamel of the incisors. Shotwell (1970) described Procastoroides idahoensis from the late Blancan Jackass Butte locality of the Grand View LF of Idaho and referred to this species two partial skeletons from Castle Butte (Grand View LF) and miscellaneous specimens from Shoofly Creek, Idaho. This species has also been recognized in the Seneca LF of Nebraska (Martin and Schultz, 1985). It is distinguished by crenulations or longitudinal grooves on the enamel of the incisors and, for this reason, Procastoroides is considered by some workers to be ancestral to Castoroides. Woodburne (1961) did not believe this to be the case based on the absence of crenulations on the incisors of P. sweeti, the only known species at the time. Flynn and Jacobs (2007) suggest that P. idahoensis could be regarded as an early species of Castoroides. Zakrzewski (1969) described Dipoides intermedius from the early Blancan Hagerman LF of Idaho. He considered it to be the largest known species of Dipoides. Xu (1995) transferred this species to Procastoroides.

Family GeomyidaeGeomys (Nerterogeomys) cf. minor Gidley, 1922

Figures 18H-IReferred specimens. Pit C: 4321, left dentary with incisor and p4-

m3; 4322, left dentary with incisor and p4-m3; 4323, left dentary with incisor and p4-m2; 4324, right dentary with incisor and p4-m1; 4325, palate with right and left P4-M1; 4326 (in part), isolated teeth. Pit D: 4033 (in part), isolated teeth.

Description. All of the dentaries are from adults and are broken just posterior to the cheek teeth preserved in each. In addition, most of the bone labial to the cheek teeth is missing, except in 4321, the most completely preserved specimen, in which the anterior part of the masseteric crest can be seen (Fig. 18I). In all of the dentaries, enough of the labial wall is preserved to show that the mental foramen lies 1. 5 to 2. 3 below and slightly anterior to the anterior extremity of the masseteric crest, which is the criterion for assignment to Nerterogeomys (Gazin, 1942) that Hibbard (1967) redefined and changed in rank from genus to subgenus. That portion of the dentaries containing the masseteric pit or fossa is missing in all specimens. In 4321 enough of the labial wall of m3 is preserved to indicate that a deep pit was present, although its exact shape and depth are unknown because the base of the ascending ramus is missing. In the p4s the enamel is interrupted by dentine tracts on the internal and external surfaces of both the protolophid (anterior lophid) and the metalophid (posterior lophid). The reentrants are U-shaped to bluntly V-shaped or squarish in occlusal view and are filled with cementum. The protolophid is sub circular and longer than wide but narrower than the metalophid. The metalophid is wider than long, and enamel is present on the posterior surface. The lower molars are ellipsoidal on the occlusal surfaces, wider than long, and possess enamel only on their posterior surfaces. The depth of the jaw below the middle of the diastema in the four consecutively numbered dentaries is 5. 6, 4. 4, 4. 0 (est. ), and 5. 0, respectively. The labial jaw depth below p4 is 8. 8 in 4321 and 7. 5 (est. ) in 4322. Other measurements, including those of the type specimen of Nerterogeomys minor, are given in Table 5.

A palate, 4325, containing the left and right P4 and M1, is referred to Nerterogeomys. The protoloph (anteroloph) and metaloph (posteroloph) in P4 are equal in width and wider than long. Dentine tracts have not yet developed. The reentrants are squared or U-shaped and filled with cementum, and there is no enamel on the posterior face of the metaloph. M1 is wider than long and possesses enamel on both anterior and posterior surfaces separated by thin labial and lingual dentine tracts. Measurements of the left teeth are: AP L of P4 = 1. 6, width of metaloph of P4 = 1. 6; AP L of M1 = 1. 0, TW of M1 = 1. 8. Palatal width across the P4s is 5. 0 and across the M1s is 5. 4. The prominent medial crest, which extends along the ventral midline of the palate, becomes less pronounced anterior to P4 but remains distinct nearly to the anterior palatine (incisive) foramina.

In the collection are numerous isolated teeth of both adult and immature gophers from both Pit C and Pit D. The upper incisors are bisulcate, as in Holocene Geomys. The average width of the metalophid

of 40 adult p4s from Pit C is 1. 83 (1. 7-2. 0) and of 22 p4s from Pit D is 1. 8 (1. 5-2. 1). The reentrant pattern varies from U-shaped to bluntly V-shaped. In adult p4s, the enamel pattern is interrupted by dentine tracts on the labial and lingual surfaces of both protolophid and metalophid. There are 46 adult P4s from Pit C. The average width of the metaloph is 1. 75 (1. 6-1. 9). Seven P4s are of young individuals and have continuous enamel bands around the occlusal surface. With wear, this pattern will be interrupted by labial and lingual dentine tracts on the protoloph and the enamel on the posterior face of the metaloph will disappear as it has in all but one of the adult P4s in the sample. A single left adult P4 has a band of enamel running the length of the tooth on the labial one-third of the posterior surface of the metaloph and separated from the labial reentrant enamel by a thin dentine tract. The average TW of 14 P4s from Pit D is 1. 7 (1. 5-1. 9). The reentrants are squared, U-shaped or bluntly V-shaped. The M1s are like those in the palate, 4325.

Remarks. Czaplewski (1990) noted that, based on Hibbard’s redefinition of Nerterogeomys, six species can be assigned to that subgenus, Geomys minor (smallest), G. persimilis, G. smithi, G. anzensis, G. garbanii, and G. paenebursarius (largest). He pointed out, however, that intraspecific morphological measurements of modern pocket gophers can be highly variable and that interspecific measurements may overlap. In addition, he noted that many authors have documented pronounced age variation and sexual dimorphism in size in modern pocket gophers. Similarly, he concluded that size may not be the best indicator of species differences among extinct pocket gophers, and that some fossil species might represent age variants or different sexes of the same widespread species. Therefore, size must be used with caution, and only adult measurements should be compared.

The dentaries from the Red Corral LF differ from those of Geomys (Nerterogeomys) smithi Hibbard (1967) from the Fox Canyon LF of Kansas in having a shorter diastema, except for 4321, and a shorter occlusal length of the tooth row. The occlusal length of the paratype of G. (N. ) smithi is shorter than that of the holotype and only slightly greater than that of the Red Corral specimens, but it is from a younger individual than the holotype.

Three of the four Red Corral specimens are smaller in all measurements than those of Geomys (N. ) paenebursarius from the Hudspeth (Strain, 1966) and Red Light (Akersten, 1972) local faunas of west Texas. The measurements of 4321 compare closely with those of the holotype and paratype specimens from Hudspeth. However, 4321 is probably an older individual while, according to Akersten (1972, p. 16), the types of G. (N. ) paenebursarius appear to be younger individuals (with shorter diastemas) than those from the Red Light LF. Considering the fact that the size of gopher jaws increases with age, it seems more reasonable to attribute the greater diastemal and occlusal lengths of 4321 to age, sexual, or individual variation than to postulate the existence of a second and larger species of Nerterogeomys in the Red Corral LF.

The Red Corral dentaries, with the exception of 4321, compare most favorably with the holotype of Geomys (N. ) minor from the Benson LF of Arizona (Gidley, 1922; Gazin, 1942). The small gopher from the Rexroad LF assigned to G. (N. ) minor by Hibbard (1967) is smaller than both the holotype and Red Corral specimens. Larger samples from the Kansas, Texas, and Arizona faunas are needed, however, to show the range of variation in the various populations. A recent analysis of gopher evolutionary lineages in the Meade Basin of southwestern Kansas is provided by Martin et al. (2011). Geomys minor appears to have had a long biochronologic range in the Blancan.

Geomys sp. - largeReferred specimens. Pit C: 4326 (in part), isolated teeth. Pit D:

4033 (in part), isolated teeth. Description and remarks. Although most of the isolated gopher

teeth from the Red Corral LF are small and are most likely assignable to Nerterogeomys, some of the teeth are distinctly much larger than any previously reported for that subgenus. Eshelman (1975) noted that gophers are unusual rodents in that the jaw and dentition increase considerably in size with age; moreover, the degree of sexual variation is great. The presence of two distinct tooth sizes in the Red Corral LF does not appear to reflect age or sexual variation, however, but rather suggests the presence of two species because (1) there is a large and distinct size difference, (2) several large p4s and P4s belong to young individuals as evidenced by uninterrupted enamel bands around the occlusal surface, and (3) there is a disproportionately smaller number of the large teeth, especially from Pit C.

20

In the collection from Pit C are a bisulcate upper incisor (width = 3. 2) and two p4s in which the width of the posterolophid is 2. 5 and 2. 7. Among the teeth from Pit D are two large bisulcate upper incisors which are 3. 4 and 3. 6 wide. The average width of the metaloph of 10 P4s is 2. 5 (2. 3-2. 7) and of the metalophid of 8 p4s is 2. 7 (2. 4-2. 9). These teeth fall within the range of Geomys jacobi from the Rexroad LF (Hibbard, 1967) and G. quinni from the Sand Draw LF of Nebraska (McGrew, 1944; Franzen, 1947; Skinner et al., 1972) and the Deer Park LF from Kansas (Hibbard, 1956) but without skulls or mandibles with complete dentitions, specific identification is not possible.

Family HeteromyidaeProdipodomys cf. idahoensis Hibbard, 1962

Figures 19A-FReferred specimens. Pit C: 4327-4333, five right and two left

tooth-bearing maxillary fragments; 4334, edentulous left maxillary fragment; 4335-4344, five left and five right tooth-bearing partial dentaries; 4345, isolated cheek teeth; 4346, dp4; 4347, upper incisors. Pit D: 4034, right dentary fragment with p4-m1; 4139, right dentary with m1; 4035, isolated teeth.

Description. Nearly all of the dentaries and maxillaries are fragmentary, and many from Pit C were concentrated in a small area of the quarry, possibly as a result of owl predation. P4 and p4 are the most frequently preserved teeth, followed by M1 and m1 (Figs. 19A-F). M2 and m2 are preserved in only one maxillary and dentary fragment (Fig. 19C) respectively. M3 and m3 are missing from all specimens. The teeth vary in age from very young to old adults.

The occlusal pattern of the teeth is basically like that of Prodipodomys centralis from Rexroad Locality 3 and the Wendell Fox locality in Kansas and P. idahoensis from Hagerman, Idaho. The lingual and labial reentrants separating the lophs (-ids) are shallower than those of P. centralis in comparable wear stages. The lingual cusp of P4 is smaller than the labial cusp and is directed more anteriorly. M1 and M2 have C-shaped patterns; the protoloph and metaloph are connected lingually and are separated labially by shallow reentrants. In p4 of young individuals, there are two cusps on the protolophid and three cusps on the metalophid, the lophids are narrowly connected between deep labial and lingual reentrants, and there is a shallow anteromedian groove on the protolophid. With wear, the cusps and the groove disappear, and the reentrants quickly become shallow. The m1 and m2 are bilophodont and are lingually constricted. The alveolus of m3 is lingual to the incisor, the alveoli of the other teeth, and the mandibular foramen. Tooth and alveolar measurements are given in Table 6. The alveolar lengths of P4-M3 and P4-M2 in the maxillaries from Pit C are shorter than those given by Zakrzewski (1970) for P. rexroadensis (synonym of P. centralis) from Rexroad Locality 3 (5. 40-5. 56 and 4. 56-4. 66 respectively) and are within the range of those of the same species from the Wendell Fox locality (UM-K3-53) in Kansas (5. 01-5. 35 and 4. 18-4. 85 respectively).

The cheek teeth are relatively hypsodont. Dentine tracts are moderately to well-developed (0. 5-1. 5) in about 46 % (64 of 139) of the isolated teeth from Pit C and in about half of the 10 teeth from Pit D. Of the 64 teeth, 46 show low wedge-shaped tracts less than 1. 00 high. The other 18 teeth show higher, narrower tracts. Although dentine tracts are measured from the base of the surrounding enamel (Zakrzewski, 1981; Czaplewski, 1990), the true tract height of about half of the total tooth sample cannot be accurately measured because either the teeth are broken or the teeth are old and worn such that the tract intersects the occlusal surface. In general, the tracts are better developed on the lingual sides of both upper and lower teeth and are somewhat better developed on the molars than on the premolars. Dentine tracts are not apparent on the teeth in most of the jaws and maxillaries. However, slightly developed tracts are present on M1 in 4328, on P4 and M1 in 4329 and on m1 in 4340 and 4034.

P4 and M1 have three well-developed roots. An exception occurs in a left M1 in which the two posterior roots are normal, and the large anterior root is composed of two fused roots. In M2, the anterolabial root has partially or completely fused with the posterolingual root, opposite the small distinct posterolabial root. The alveolus of M3 shows that three roots have typically fused to one.

The p4 is two-rooted, but the posterior root is broad and may be composed of two fused roots. A single right p4 possesses, in addition, a tiny but distinct medial-lingual root resembling the small third root in m1 of Sigmodon minor. The m1 is double-rooted but may show a fusion of two smaller roots in both the anterior and posterior roots. In m2, the larger anterior root tends to fuse lingually with the posterior root; a thin shelf of bone in the alveolus separates the two roots labially in 4139. The m3 alveolus, preserved only in a single jaw, 4139, from Pit D, is

TABLE 5. Measurements (in mm) of dentaries and teeth of Geomys (Nerterogeomys) cf. minor from Red Corral Pit C compared with type specimen from Benson LF, Arizona.

Measurement 4321 left 4322 left 4323 left 4324

rightUSNM 10494

(type)p4-m3 6. 2 5. 5p4-m2 5 4. 6 4 5p4 length (occlusal) 2. 7 2. 4 2. 1 2. 7

p4 width 2. 1 1. 9 1. 9 1. 9 1. 9m1 length 1. 1 1. 1 0. 9 1. 1m1 width 2. 1 2 1. 8 2 2m2 length 1. 1 1. 1 1m2 width 2 2 1. 7m3 length 1. 1 0. 9m3 width 1. 5 1. 5incisor width 2. 2 2 1. 75 2 2. 1diastemal length 7. 4 5. 6 5. 8 5. 6 5. 4

diastemal width 3. 6 3. 2 2. 8 3. 5 3. 5

jaw depth at p4 8. 8 c. 7. 5

TABLE 6. Statistical summary of jaw and tooth measurements (in mm) of Prodipodomys idahoensis from Red Corral sites and Hagerman LF, Idaho. V prefix = UMMP specimen.

Red Corral Pit C Pit D Hagerman

Metric N OR Mean SD

Upper V50074P4-M1 occlusal length

4 1.9-2.5 2. 19 0. 213

P4 length 7 0.9-1.2 1. 06 0. 105 1. 4P4 anterior width 7 0.4-0.7 0. 59 0. 099P4 posterior width 7 1.1-1.5 1. 27 0. 138 1. 6

M1 length 4 0.9-1.1 1 0. 071

M1 width 4 1.3-1.6 1. 45 0. 112

M2 length 1 0. 9 0. 9 0

M2 width 1 1. 2 1. 2 0

Lower #4034 V50220 V50221 V52740 V53449p4-m1 occlusal length

4 1.9-2.6 2. 23 0. 286 2. 4

p4 length 9 0.9-1.25 1. 13 0. 108 1. 4 1. 3 1. 6 1. 4

p4 anterior width 9 0.9-1.2 1. 11 0. 107 1. 1

p4 posterior width 9 1.15-1.6 1. 39 0. 159 1. 3 1. 45 1. 4 1. 5

m1 length 4 0.9-1.2 1. 06 0. 119 1. 05 1 1. 05/1

m1 width 4 1.2-1.5 1. 38 0. 13 1. 5 1. 6 1. 5/1. 5

m2 length 1 1.1 1. 1 0 1 1

m2 width 1 1.5 1. 5 0 1. 5 1. 6

approx. jaw depth 7 3.6-4.4 4. 04 0. 261

diastema length 7 3.4-4.6 3. 93 0. 42

21

FIGURE 19. Prodipodomys cf. idahoensis: A, right maxillary, P4-M1, 4328, Pit C; B, dp4, 4346, Pit C; C, right dentary fragment, p4-m1, 4034, Pit D; D, right dentary with incisor, p4-m1, 4340, Pit C; E, right dentary with incisor, adult p4 in dp4 alveolus, m1 alveolus, occlusal view, 4342, Pit C; F, right dentary with m1 and alveoli for p4, m2, and m3, 4139, Pit D. Perognathus cf. pearlettensis: G, right dentary with incisor, p4-m2, 4362, Pit C; H, left dentary, p4-m2, 4360, Pit C. Perognathus cf. gidleyi: I, right dentary with incisor, p4-m1, 4140, Pit D.

22single-rooted.

The Red Corral specimens have equally or slightly less developed roots than Prodipodomys rexroadensis (Hibbard, 1954), which Skinner et al. (1972) synonymized with P. “Liomys” centralis (Hibbard, 1941b). Root development in the holotype maxillary of “P. rexroadensis,” UMMP 29688, is comparable to that in the Red Corral maxillaries except that the three roots in M2 are a little more distinct, although the anterolabial and lingual roots are slightly fused. The same is true for M2 in the partial skull of P. centralis from the Sand Draw LF of Nebraska (Skinner et al., 1972). Hibbard (1962, p. 482) stated also that m3 of this species has two well-developed roots.

Hibbard (1962, p. 482) and Zakrzewski (1969, p. 12) diagnosed Prodipodomys idahoensis as being the size of P. rexroadensis (P. centralis) but having more hypsodont teeth with roots that are not as well-developed. Since no maxillaries or upper molars of P. idahoensis were reported, their statement about root development must be limited to the lower teeth and a single left P4. Hibbard described the alveolus of m2 in the holotype, USNM 22754, an adult, as deep and indicating the presence of a small labial root that had nearly completed coalescence with the large lingual root. Zakrzewski (1969) stated that the development of the roots of the teeth in this species is similar to that observed in Etadonomys tiheni from the latest Blancan Borchers LF of Kansas, which he later referred to the genus Prodipodomys. . According to Hibbard (1943, p. 186), in the Borchers species, p4 and m1 have two roots while m2 and m3 are single-rooted. It appears from the available material that root development in adult specimens of P. idahoensis and the Red Corral kangaroo rat is comparable. A series of maxillaries is needed to determine the extent of root reduction and fusion in M2.

The mandibular foramen, preserved only in 4139, is dorsal and slightly lingual to the incisor (Fig. 19F). In Prodipodomys griggsorum from the earliest Blancan Saw Rock Canyon LF of Kansas and in P. idahoensis the foramen is lingual to the incisor whereas, in P. kansensis from the Hemphillian Edson LF of Kansas, it is on the labial side (Zakrzewski, 1970). In 4139, the only Red Corral specimen in which the posterior part of the dentary is preserved, there is no pit or fossa between the teeth and the ascending ramus as is found in most Holocene species of Dipodomys, and the shelf above the foramen is nearly level with the alveolar ridge, as in P. griggsorum and P. idahoensis. In P. centralis, a shallow depression occurs in this position whereas in the two described dentaries of P. tiheni a pit or fossa occurs dorsal and labial to the mandibular foramen (Zakrzewski, 1981, p. 79). In most Holocene specimens of Dipodomys, the mandibular foramen is typically located in a pit labial to the incisor, although in some specimens the pit lies dorsal and labial to the foramen or is absent altogether. Zakrzewski (1981), noting the variability of the relationship of foramen to fossa in both Prodipodomys and Dipodomys, considered this feature to be unreliable as a taxonomic character at the generic level.

The capsular process for the base of the incisor in 4139 is on the labial side of the jaw 2. 0 posterior to the anterior border of the mandibular foramen. The masseteric ridge in some specimens from Pit C ends in a pronounced knob that extends above the ventral surface of the diastema as in Prodipodomys centralis, whereas in other specimens from both Pits C and D, the knob is less pronounced and more ventral, a characteristic which Skinner et al. (1972) used to distinguish P. idahoensis from P. centralis but which appears to vary intraspecifically. Jaw and tooth measurements of the Red Corral specimens and those from Hagerman are summarized in Table 6.

Remarks. The distinction between Dipodomys and its presumed ancestor Prodipodomys was clarified by Zakrzewski (1981) who emended the diagnosis of both genera based primarily on crown height of the teeth rather than root loss. He observed that the crown height in adults of Dipodomys generally exceeds the length of the root, whereas the crown height in adults of Prodipodomys is approximately the same as the root length. The root in Dipodomys is generally a tubular continuum of the crown. The molars of Dipodomys are single-rooted in advanced species whereas primitive species may possess molars with more than one root but they are generally fused rather than independent. The p4 is two-rooted and P4 three-rooted in primitive species whereas in advanced species, the premolars become single-rooted through fusion. Zakrzewski (1981) noted that in Prodipodomys evidence for two or more roots is easily observable on each of the teeth. In Dipodomys, dentine tracts are well-developed whereas in Prodipodomys dentine tracts are absent or only slightly developed. In Prodipodomys, a distinct anterocone is generally present on P4 whereas in Dipodomys the anterocone is lost early with wear.

Prodipodomys idahoensis is distinguished from P. kansensis,

P. griggsorum, and P. minor from the early Blancan Benson LF of Arizona, by its larger size, greater root reduction, and more hypsodont teeth with dentine tracts. P. idahoensis is the same size as P. centralis but differs from it in having teeth that are more hypsodont with shallower reentrants and slightly less-developed roots and, possibly, in the absence of a shallow depression dorsal and labial to the mandibular foramen. Unlike P. idahoensis, P. centralis is said to completely lack dentine tracts, although Czaplewski (1990) interpreted emarginations of enamel at the lateral bases of the tooth roots as broad, incipient dentine tracts (see below). Comparisons between P. idahoensis and P. tiheni remain obscure. Zakrzewski (1981) provided an emended diagnosis of P. tiheni stating that it “is distinguished from other species in the genus by being more hypsodont, having slightly higher dentine tracts, and a somewhat deeper masseteric fossa.” He also noted that “dentine tracts are absent or only slightly developed in Prodipodomys and seldom exceed 0. 7 mm in height whereas tracts in Dipodomys are generally greater than 1. 0 mm and seldom are less than 0. 9 mm. ” Tomida (1987, p. 70) noted a contradiction in that at least some teeth of P. idahoensis actually have much higher dentine tracts than P. tiheni. Those of two isolated m1s of P. idahoensis are 1. 59 and 1. 38 in height according to Zakrzewski (1969, p. 12) and are well within the range of Dipodomys hibbardi from 111 Ranch, Arizona. Czaplewski (1990) assigned to Prodipodomys idahoensis a sizeable sample of dentaries, maxillaries, and isolated teeth from the early Blancan Verde LF of Arizona. He noted (p. 23) the presence of emarginations of enamel at the lateral bases of the roots in some specimens of P. centralis illustrated by Hibbard (Skinner et al., 1972) and interpreted these as broad, incipient dentine tracts noting also that similar broad, rounded emarginations at the bases of roots in cheek teeth of P. tiheni were called dentine tracts by Zakrzewski (1981). Czaplewski suggested that “perhaps the presumed differences in presence or absence of dentine tracts in some Prodipodomys species are merely differences in authors’ perceptions or definitions of a dentine tract.” He illustrated a way of measuring the height of a dentine tract from the base of the enamel crown (Czaplewski, 1990, p. 19). More recently, Ruez (2009) noted that “of all of the species of the genus, P. idahoensis, especially the Hagerman, Idaho specimens, shows the greatest development of dentine tracts and the greatest degree of hypsodonty.” Presumably, at first glance, it would seem that P. idahoensis differs from P. tiheni in its smaller size, more poorly developed roots, better developed dentine tracts, the absence of a temporal pit or fossa dorsolabial to the mandibular foramen, and the more lingual placement of the m3 alveolus with respect to the foramen. However, it would appear that dentine tract height and the development of a temporal pit or fossa are quite variable within and between species of both Prodipodomys and Dipodomys. Unfortunately, sample size from the type localities of both P. idahoensis and P. tiheni is quite small. The former is represented by four dentary fragments and three isolated teeth from the Hagerman LF of Idaho and the latter by two dentaries from the Borchers LF of Kansas. No maxillaries have been reported.

Albright (1999) assigned to Prodipodomys idahoensis a significant sample of specimens from the San Timoteo Badlands in California, and the species has been recognized in other Blancan faunas as well. Kangaroo rat specimens from Wolf Ranch, Arizona, were referred by Harrison (1978) to P. idahoensis; however, they have higher, narrower dentine tracts and a greater amount of root fusion. Tomida (1987) and Czaplewski (1990) suggested that they might represent a more advanced kangaroo rat such as Dipodomys hibbardi. Recently, both identifications were considered correct because both taxa were recognized from Wolf Ranch (Albright, 1999; Ruez, 2009). Mou (2011b) recognized a small and a large species of Prodipodomys in the early Blancan Panaca LF of Nevada. The smaller species was assigned to P. minor Gidley because of its small size and the fusion of roots in both upper and lower cheek teeth. Incipient dentine tracts were noted on the sides of p4. Mou assigned the larger species to P. tiheni and noted that the cheek teeth are significantly larger and slightly higher crowned than those of P. minor and that they possess low dentine tracts. Mou compared P. tiheni with P. centralis of similar size but made no comparisons between P. tiheni and P. idahoensis. Dalquest et al. (1992) commented that it is still unclear how species of Prodipodomys are related to each other or to species of Dipodomys. Pending the discovery of additional fossils and/or a revision of the genus Prodipodomys, I tentatively refer the Red Corral kangaroo rat to P. idahoensis.

Perognathus cf. gidleyi Hibbard, 1941b, cFigure 19I

Referred specimens. Pit C: 4348-4358, six left and five right

23m3 are lacking.

The Red Corral specimens were compared with the holotype and topotypes of Perognathus gidleyi from Rexroad Locality 3 (Hibbard, 1941b, c ) and additional material from the Borchers LF (Hibbard, 1941a) as well as with a series of P. rexroadensis jaws from the Fox Canyon LF (Hibbard, 1950). They most closely resemble P. gidleyi in the dimensions of the teeth and in the pattern of p4, although the jaws are about 7 % shallower and the diastema is about 20 % shorter (Table 7).

The metalophid of p4 is distinctly wider than the hypolophid (= protolophid), and the posterior cusps are larger and more widely separated from each other than the anterior cusps. The anteromedian groove is only slightly developed. The labial and lingual reentrants are about equally deep, but the lingual one may be wider, resulting in a central union of the metalophid and the hypolophid. The m1 is bilophodont, and the labial stylids are weakly developed compared to the lingual and medial cusps. The teeth vary from young to mature adult.

The masseteric ridge slopes at about a 35 degree angle and does not extend to the top of the diastema. The mental foramen is below or slightly ahead of the anterior extremity of the ridge.

Tooth and jaw measurements of Perognathus gidleyi and P. rexroadensis are summarized in Table 7. P. rexroadensis is larger than P. gidleyi. The jaw is about 20 % deeper, the diastema is about 13 % longer, and the tooth row is about 8 to 10 % longer. The p4 of P. rexroadensis differs from that of P. gidleyi in that the lingual reentrant valley is deeper than the labial valley, resulting in a more labial connection of the metalophid and the hypolophid. P. mclaughlini from the Saw Rock Canyon LF is the size of P. gidleyi but the p4 pattern is like that of P. rexroadensis in having the deeper lingual reentrant valley. P. maldei is about the size of P. gidleyi but reportedly possesses a well-developed hypostylid on p4. P. pearlettensis, P. henryredfieldi, and P. dunklei are smaller species. P. strigipredus from the early Blancan Verde LF of Arizona has a relatively wider metalophid on the p4 that is nearly as wide as the hypolophid, deeper labial and lingual reentrants on p4, and m1 that is anteroposteriorly compressed and higher crowned. The reader is referred to Czaplewski (1990) and Mou (2011b) for further comparisons among fossil species.

Remarks. Pocket mice are frequent targets for predation by owls, and this may account for the local abundance of these forms in the fauna although no fossilized pellets were found. The larger species, Perognathus cf. gidleyi, is slightly more abundant than the smaller species, P. cf. pearlettensis.

Perognathus cf. pearlettensis Hibbard, 1941aFigures 19G-H

Referred specimens. Pit C: 4360-4367, two left and six right dentaries and dentary fragments; 4368, much worn lower left dentition lacking m3; 4369, right maxillary with P4-M1.

Description. As with the larger species described above, this small pocket mouse is represented by a series of partial dentaries or dentary fragments (Figs. 19G-H), most of which came from a small area of Pit C. Most are bleached and some are fractured. The jaws are broken posterior to p4, m1, or m2. The absence of m3s can be explained by several factors, including their small size and loss during digestive, taphonomic, and screen washing processes.

The jaws and teeth were compared with paratypes of Perognathus pearlettensis from the Borchers LF (Hibbard, 1941a) and other specimens from Fox Canyon (Hibbard, 1950) and they show no significant differences except their slightly smaller size. The pattern of p4 is like that of P. pearlettensis. The tooth is sub-quadrate with the four well-developed cusps separated in younger teeth by deep, vertical valleys. In one specimen, 4361, there is a very low medial cusp on the metalophid. In occlusal view, the anterior, labial, and lingual reentrant valleys appear shallow; the lingual reentrant is slightly wider and deeper than the labial reentrant thus giving the protoconid-hypoconid connection a more labial position as seen in P. pearlettensis. With further wear, the cusps will present an X-pattern. The m1 and m2 are bilophodont. The labial stylids are less developed than the lingual cusps, and the hypostylid of m2 is especially weak. The tooth roots are not exposed.

The masseteric crest extends at about a 45 degree angle to the top of the diastema and terminates ventrolateral to the posterior part of the diastema. The mental foramen is ventral to the anterior extremity of this ridge, as in Perognathus pearlettensis. None of the dentaries is complete enough to show any features of the posterior region.

TABLE 7. Statistical summary of jaw and tooth measurements (in mm) of Perognathus from Red Corral and other Blancan local faunas.

Measurement N OR Mean SDPerognathus cf. gidleyi Red Corral Pit C R.C.

Pit D Rexroad

#4140 KU 4775 type

p4 length 8 0.75-0.9 0.82 0.053 0.7 0.8p4 width 8 0.75-0.9 0.84 0.058 0.85 0.8m1 length 5 1.0-1.15 1.04 0.065 1 1.1m1 width 5 1.1-1.2 1.14 0.042 1.05 1.15p4-m1 length 4 1.85-1.95 1.88 0.05 1.7 1.85lingual jaw depth below p4 8 2.5-2.7 2.55 0.076 2.7 2.5labial jaw depth below p4 9 2.7-3.1 2.94 0.124 3 2.9

diastema length 6 2.9-3.2 3 0.11 3min. diastema width 10 0.8-1.1 0.94 0.084 1.1 1Perognathus. rexroadensis Fox Canyonp4 length 3 0.8-0.9 0.87 0.058p4 width 9 0.8-1.0 0.89 0.054m1 length 3 1.1-1.2 1.15 0.05m1 width 9 1.0-1.3 1.2 0.085p4-m1 length 3 1.9-2.1 2.02 0.104lingual jaw depth below p4 6 3.1-3.7 3.22 0.238labial jaw depth below p4 3 3.7-3.9 3.8 0.1

diastema length 3 3.8-4.2 4 0.2min. diastema width 3 1.3 1.3 0

Measurement N OR Mean SDPerognathus cf. pearlettensis Red Corral Pit Cp4 length 6 0.55-0.6 0.58 0.027p4 width 6 0.55-0.6 0.59 0.02m1 length 4 0.75-0.9 0.85 0.071m1 width 4 0.75-0.9 0.86 0.075p4-m1 length 4 1.35-1.5 1.43 0.065m2 length 3 0.65-0.8 0.73 0.076m2 width 3 0.75-0.9 0.85 0.087lingual jaw depth below p4 4 1.7-2.3 2 0.245labial jaw depth below p4 4 2.0-2.5 2.3 0.216

diastema length 3 2.0-2.7 2.3 0.361min. diastema width 4 0.6-0.9 0.79 0.131Perognathus pearlettensis Borchers LF.p4 length 5 0.65-0.75 0.69 0.042p4 width 4 0.6-0.7 0.66 0.048m1 length 2 0.95 0.95 0m1 width 2 0.95-1.0 0.98 0.035p4-m1 length 2 1.5-1.65 1.58 0.106m2 length 3 0.8-0.9 0.87 0.058m2 width 3 0.9-1.0 0.97 0.058lingual jaw depth below p4 3 2.0-2.4 2.2 0.2labial jaw depth below p4 5 2.5-2.8 2.64 0.152

diastema length 1 2.1 2.1 0min. diastema width 3 0.9 0.9 0

tooth-bearing partial dentaries; 4359, left P4, left M1. Pit D: 4140, right dentary with incisor, p4-m1; 4141, right dentary fragment with p4.

Description. A medium-sized pocket mouse is represented by a series of partial dentaries, most of which came from a very small area of Pit C and may have been concentrated there by owl predation although no fossil owl pellets were found. Nearly all of the dentaries are broken posterior to p4 or m1 (Fig. 19I) and some are bleached and fractured. The p4 is the most frequently preserved tooth followed by m1; m2 and

24

Measurements of jaws and teeth from Red Corral Pit C and Borchers (type locality) are summarized in Table 7. Measurements of specimens from Fox Canyon are not given, although the Fox Canyon and Borchers specimens are nearly identical in size. The Red Corral specimens average 12 % shorter tooth row, 12 % shallower jaw depth, 8 % shallower diastema, and 17 % narrower incisor. There is virtually no overlap in size ranges between the Red Corral and Borchers samples, although in several measurements the largest values for Red Corral equal the smallest for Borchers.

Remarks. The joint occurrence of at least two species of Perognathus in a fauna is common. Two forms, one large and one small, are recognized from the Fox Canyon (Hibbard, 1950), Hagerman

(Zakrzewski, 1969), Wolf Ranch (Harrison, 1978), Verde (Czaplewski, 1990), Blanco (Dalquest, 1975), White Rock (Eshelman, 1975), and Borchers (Hibbard, 1941a, 1942) local faunas. Dalquest (1978) reported three distinctly different-sized species from the Beck Ranch LF of Texas.

Most authors have assigned, at least tentatively, the small species of pocket mouse from Blancan faunas in the Great Plains and Arizona to Perognathus pearlettensis because of a general similarity in size and dental characteristics, and I have followed that practice for the Red Corral specimens. Because these specimens are smaller than those from either Fox Canyon or Borchers, it is entirely possible that another species is represented in the fauna. However, in the absence of other

FIGURE 20. Peromyscus sp. (large): A, right dentary with incisor, m1-m2, 4145, Pit D; B, right dentary, m1-m2, 4039, Pit D. Reithrodontomys cf. rexroadensis: C, right dentary with incisor, m1-m2, 4393, Pit C. Onychomys cf. pedroensis: D,left M1, 4402, Pit C. Bensonomys cf. arizonae: E, right dentary with incisor, m1-m3, 4037, Pit D; F, left dentary, m1-m2, 4143, Pit D.

25detectable significant differences, I am reluctant to establish a new species on the basis of size alone.

Dalquest (1975) observed that specimens from the Blanco LF referred to Perognathus pearlettensis were a trifle smaller than the topotypes with which they were compared. He noted that teeth and jaws of Perognathus offer few characters, other than actual and relative size of teeth that are diagnostic at the specific level. Pocket mice are common mammals of the arid plains and deserts of the Southwest today, and several species often occur together. Unfortunately, morphological differences between extant species, particularly the smaller species such as P. flavus, P. flavescens, and P. merriami, and even between the extant genera Perognathus and Chaetodipus, may not be apparent in teeth and jaws making assignment to species and even to genus problematical. In view of this, the small Blancan pocket mice may well represent more than one species. Better fossil material and greater resolution of age differences in Blancan faunas are necessary before this can be feasibly determined.

Family CricetidaeSubfamily CricetinaePeromyscus sp. - large

Figures 20A-BReferred specimens. Pit C: 4388, right dentary fragment with m2;

4389, right m1. Pit D: 4039, right dentary fragment with m1-m2; 4040, left dentary fragment with m1; 4145, right dentary with incisor, m1-m2.

Description. Remains of Peromyscus are relatively rare in the Red Corral LF and in Blancan faunas in general. The most complete specimen from the Red Corral LF, 4145 (Fig. 20A), is that of a large deer mouse the size of the Holocene Peromyscus leucopus. The jaw is that of a fairly young adult and is broken across the alveolus of m3. The occlusal length of m1-m2 is 2. 95. The m1 is subrectangular in occlusal outline. The anteroconid is moderately broad, bluntly rounded and is slightly divided by an anteromedial notch or flexid. The metaconid is separated from the anteroconid by a deep, narrow anterointernal valley. The remaining valleys and folds are deep and V-shaped. A prominent, slightly serrated ectocingulum connects the protoconid and hypoconid. A prominent mesocingulum connecting the metaconid and entoconid is raised to form a small mesostylid. The posterior cingulum is well-developed. The m1 is 1. 6 long and 1. 1 wide. The m2 is rectangular shaped. Small cingula are present in both labial and lingual valleys. The posterior cingulum is wide. The tooth is 1. 35 long and 1. 1 wide. The diastema is 3. 3 long and 1. 15 wide (minimum). The width of the incisor is 0. 6. The dorsal and ventral ridges of the masseteric crest are sharply defined and terminate in a prominent ridge below the anterior root of m1. The mental foramen is 0. 3 anterior to and 0. 5 below this ridge. The labial jaw depth below m1 is 3. 6.

A right dentary fragment, 4039 (Fig. 20B) is that of a young adult and is similar to 4145. It is broken across the diastema and posterior to m2. The incisor and ventral portion are missing. The occlusal length of m1-m2 is 3. 05. The m1 is subrectangular. The anteroconid is broad and bluntly rounded but is not divided anteromedially. The anterolophid is separated from the anteroconid by a slight indentation. The anterointernal valley between the anteroconid and the metaconid is not as narrow as in 4145. An ectostylid and a mesostylid are present. The posterior cingulum is wide and connects with the entoconid to enclose a small pit. The m1 is 1. 7 long and 1. 1 wide. The m2 is rectangular and possesses a prominent anterolophid, a good mesostylid, and a weak ectocingulum. The posterior cingulum is less developed than in 4145 and is weakly joined to the entoconid. The m2 is 1. 35 long and 1. 1 wide. The mental foramen is situated near the top of the labial surface about 1. 0 ahead of the masseteric crest, which is not as prominent as in 4145.

A left dentary fragment, 4040, is that of a mature adult. The ventral and posterior portions are missing. The only tooth present is m1, which resembles that in the other jaws. The anteroconid is broad and bluntly rounded and very slightly notched anteromedially. The anterolophid is not distinct from the anteroconid. A small ectocingulum and mesocingulum are present. The m1 is 1. 65 long and 1. 1 wide. The alveolar length of m1-m3 is 4. 0. The diastema is 3. 0 long and 1. 0 wide. The mental foramen is 0. 7 anterior to and slightly below the masseteric crest which resembles that in 4039.

A right dentary fragment with m2 and part of the incisor, 4388, is that of an old adult. It is broken across the alveolus of m1, but a portion of the ascending ramus is preserved. The occlusal surface of m2 is worn nearly flat and is 1. 3 long and 1. 0 wide. Weak labial and lingual cingula are present. A shallow sulcus is present above the capsular process. The

labial jaw depth below m1 is 3. 3. A right m1, 4389, of a young adult resembles the others in possessing

a broad, bluntly rounded, anteromedially notched anteroconid. A poor ectocingulum and a weak mesocingulum are present. The tooth is 1. 6 long and 1. 05 wide.

No upper teeth or maxillaries are present in the sample from either Pit C or D.

Remarks. Six species of Peromyscus have been reported from Blancan faunas in the Great Plains. Two of these, P. sawrockensis and P. beckensis, were later referred to the genus Symmetrodontomys – the former by Martin (2000) and the latter by Dalquest (1980). The remaining four include two large species: P. kansasensis and P. hagermanensis and two smaller species: P. baumgartneri and P. cragini. The large Peromyscus specimens from Red Corral were compared with the holotype of P. kansasensis from Rexroad Locality 3, Meade County, Kansas, and with published descriptions of P. hagermanensis from the Blancan Hagerman LF of Idaho. The holotype of P. kansasensis is a right dentary, KU 4597, described by Hibbard (1941b, c). The incisor and m1-m3 are present. The teeth are large and uncrowded with low cusps and wide valleys between the cusps. There are no lophids or stylids. The m1 is longer and narrower than that of the Red Corral specimens and appears to lack an anteromedial notch on the anteroconid. Measurements of the holotype are: m1-m3 = 4. 1, m1 = 1. 65 long and 1. 05 wide; m2 = 1. 35 long and 1. 05 wide; m3 = 1. 1 long and 0. 9 wide; diastema = 3. 0 long and 1. 1 wide (minimal); labial jaw depth below m1 = 3. 0. No other specimens from the type locality are known.

More recently, Skinner et al. (1972) referred to this species a maxillary from the Sand Draw LF of Brown County, Nebraska, and Dalquest (1978) referred a series of dentaries from the Beck Ranch LF of Scurry County, Texas. Dalquest (1978) stated that the Beck Ranch jaws have teeth a bit smaller than those from Kansas, but that no other difference can be detected. He gave no measurements and I have not had an opportunity to examine these specimens which may or may not belong to this species. The Red Corral jaws do not closely resemble the holotype of Peromyscus kansasensis and, in the absence of topotypes, that could give the range of variation, I cannot justify assigning the large Red Corral mouse to this species.

Peromyscus hagermanensis was originally described from the Hagerman LF in Idaho by Hibbard (1962). Additional specimens were described by Zakrzewski (1969), and the Idaho material is represented by several parts of dentaries and maxillaries, all of which are probably too fragmentary for adequate comparison. The teeth show variation in the development of accessory lophs (-ids) and styles (-ids), which Hooper (1957) has shown to be common in the genus. A slight anteromedial notch is present on at least one of the m1s. It is possible that more than one species is present in the Hagerman LF, although Zakrzewski, recognizing the small sample size and the possible variation in dental characters, preferred to treat the Hagerman sample as one species. Another large species of Peromyscus (P. nosher) has been described from the early Blancan White Bluffs LF of Washington (Gustafson, 1978). It is similar in size and morphology to P. hagermanensis but supposedly differs in having a more distinctly bilobed anteroconid on m1.

In recent years, several workers have assigned larger specimens of Peromyscus to P. hagermanensis as a default species for want of other large species for comparison. Czaplewski (1987b) referred an upper left M1 from the Clarkdale LF in the Verde Formation of Arizona. Tomida (1987) referred a series of teeth from the Blancan Duncan and 111 Ranch local faunas from Arizona to this species. He reported a considerable range of variation in tooth dimensions but noted that the teeth were somewhat smaller than the teeth from Idaho, that many of them possessed stylids, and that the anteroconid on m1 was either unicuspid or weakly bilobate. Martin et al. (2002b) originally referred several molars from the Deer Park B LF of Meade County, Kansas, to this species, noting that the teeth were the same size or smaller than those of the Idaho species. Mou (2011a) also assigned to P. hagermanensis a fairly large sample of upper and lower molars, maxillary fragments, and dentaries from the early Blancan Panaca LF of Nevada and also reported a considerable range in tooth dimensions although, overall, the teeth were similar in size to those from Arizona. Mou also noted that the m1s varied somewhat in shape and cusp alignment and that the anteroconid was either unicuspid or weakly bilobate. There was also variation in the presence or absence of styles (-ids) and lophs(-ids). If all of these assignments are correct, P. hagermanensis would have had a large geographic range from Idaho

26to the Texas Panhandle and to Arizona, which seems very unlikely. R. A. Martin (written communication, 2015) commented that the features used to identify P. hagermanensis are so generalized they could refer to almost any ancestral Peromyscus species. He expressed the opinion that the assignment of any Great Plains Peromyscus to P. hagermanensis is probably incorrect and that he and his co-workers no longer refer Meade Basin mice to that species. For these reasons, a specific name is not applied to the Red Corral specimens at this time. Clearly, the genus is in need of revision considering the large number of fossil and extant species that have been described (30 in just the United States alone according to one count). Such a revision is beyond the scope of this paper. Martin (written communication, 2015) suggested that any such revision should involve first a general sorting to size followed by a consideration of the shape of m1 and the width of reentrant valleys, the width and symmetry of the anterocone on M1 and the anteroconid on m1, and the development of the labial cingulum. Least important would be the development of accessory structures (stylids, lophids, etc.) and whether the anteroconid is bifid or not as these features have been shown to be variable even within a species.

Peromyscus spp. – smallReferred specimens. Pit C: 4390, edentulous right dentary

fragment; 4391, right m1; 4392, right dentary with incisor, m1-m2. Pit D: 4041, left dentary fragment with m1; 4042, right dentary with m2; 4043, two right m1s and a right M1.

Description. At least two small deer mice are represented by material too fragmentary to permit species determination. A left dentary fragment, 4041, is that of a mature adult. It is broken just anterior to the mental foramen and posterior to m1. The m1 is 1. 5 long and 1. 0 wide and narrows anteriorly, giving the tooth a triangular appearance. The anteroconid is narrow and is not divided anteromedially. Valleys between the cusps are V-shaped and no cingula or stylids are present. The m1 is slightly larger than that of the type of Peromyscus baumgartneri Hibbard from Rexroad Locality 3 (Hibbard, 1954). The mental foramen is high on the labial surface of the jaw and 1. 0 in front of the anterior end of the masseteric crest.

Two right m1s, 4043a and 4043b, belong to a young and an old adult, respectively, and resemble that in 4041 but are slightly larger (both are 1. 55 long and 1. 05 wide) and have a slightly broader and more rounded anteroconid. All three m1s are broader posteriorly and more triangular in shape than those of Peromyscus cragini from the Cudahy Fauna of Kansas (Hibbard, 1944; Paulson, 1961). Another right m1, 4391, of a young adult is narrower and more rectangular than either of the other m1s. The anteroconid is broad, bluntly rounded, and slightly notched anteromedially. The valleys are deep and slightly broader. A weak ectocingulum and mesocingulum are present. The tooth is 1. 5 long and 0. 95 wide.

A right dentary, 4392, of an old adult is broken just anterior to the mental foramen but contains the incisor, m1-m2, m3 alveolus, and the lower part of the ascending ramus. The teeth are heavily worn and show no pattern. The occlusal length of m1-m2 is 2. 55, and the alveolar length of m1-m3 is 3. 4. Width of the incisor is 0. 7, and the labial jaw depth below m1 is 3. 5. A shallow sulcus is present above the capsular process. In the edentulous right dentary fragment, 4390, the alveolar length of m1-m3 is 3. 5.

A right M1, 4043c, is 1. 6 long, 1. 0 wide and possesses a small mesostyle. It probably belongs to the same species as the lower teeth.

A second small species of Peromyscus is represented by a right dentary, 4042, containing the incisor, m2 and the two-rooted alveoli for m1 and m3. The jaw is broken behind the m3 alveolus. The alveolar length of m1-m3 is 3. 2. The m2 lacks stylids and is 1. 05 long and 0. 9 wide and is slightly smaller than m2 in the type of P. baumgartneri, with which it was compared. It is about the size of m2 in Reithrodontomys wetmorei and Reithrodontomys rexroadensis from the Fox Canyon LF (Hibbard, 1952a) but is slightly shorter and wider. The late Claude W. Hibbard examined the specimen and considered it to represent a small species of Peromyscus. It is larger than Baiomys kolbi from the Fox Canyon LF (Hibbard, 1954). The width of the incisor is 0. 5 and that of the diastema (minimum) is 0. 9. The mental foramen is situated high on the labial side of the jaw just in front of the anterior root of m1. The labial jaw depth below m1 is 2. 4.

Remarks. As noted above, remains of Peromyscus are rare in Blancan faunas. Known fossil species have been described from relatively few specimens and most have been assigned to the subgenus Haplomylomys based on the absence of stylids and lophids. Hooper (1957), however, showed that the presence or absence of accessory

structures and the degree to which they are developed is highly variable in species of the genus Peromyscus.

Some of the smaller teeth from the Red Corral localities resemble the type of Peromyscus baumgartneri in size, absence of accessory cusps, and absence of an anteromedial notch on the anteroconid. The holotype of P. baumgartneri is from Rexroad Locality 3, and the paratypes are from the older Fox Canyon LF. It is possible that some of the Red Corral specimens also belong to this species, but until the geologic range and the range of morphologic variation of P. baumgartneri is better known, I hesitate to assign such fragmentary material to this species.

Another smaller species, Peromyscus cragini, has been reported from the late Blancan White Rock LF of northcentral Kansas (Eshelman, 1975). The dentary from this locality is similar to the holotype of P. cragini from the Irvingtonian age Cudahy LF of Meade County, Kansas, and to the holotype of P. baumgartneri as well. The White Rock dentary has a slightly larger mental foramen than that of the type. The diastemal width is proportionately greater than that of P. baumgartneri and more like the condition found in P. cragini. The White Rock dentary has a small anterior groove on the face of m1 and there are no accessory cusps or stylids.

Reithrodontomys cf. rexroadensis Hibbard, 1952aFigure 20C

Referred specimens. Pit C: 4393, right dentary with incisor, m1-m2; 4394, right dentary with incisor, m1-m2; 4395, right dentary with m1-m3; 4396, left dentary fragment with m1; 4397, right maxillary fragment with M1.

Description. The right dentary, 4393, is that of a young adult of a small species of harvest mouse (Fig. 20C). It lacks m3 and the coronoid, articular, and angular processes. Incisor width is 0. 45. The anteroconid of m1 is narrower than in Reithrodontomys megalotis (Baird) or R. montanus (Baird) and more pointed than in Baiomys. The anterolophid is a short cingulum joining the front of the protoconid. The anterointernal valley is deep, but the metaconid is not pressed against the anteroconid. The posteroexternal valley (major fold) between the protoconid and the hypoconid is broad, and there is a low cingulum but no ectostylid. No mesostylid is present in the deep valley between the metaconid and the entoconid. The posterior cingulum is well-developed. The m1 is 1. 3 long and 0. 8 wide. The anterolophid on m2 is not well-developed, and there is no pit between it and the protoconid. A slightly raised cingulum occurs in the major fold. The tooth is narrower posteriorly, and the posterior cingulum is poorly developed. The m2 is 1. 0 long and 0. 85 wide. The alveolus of m3 is 0. 5 long and 2-rooted. The alveolar length of m1-m3 is 2. 90. The occlusal length of m1-m2 is 2. 3. The anterior end of the diastema is broken; the minimum diastemal width is 0. 7. The mental foramen is large and dorsolabial in position but lingual to m1. The masseteric crest is very weak and terminates behind the anterior root of m1, in contrast with R. megalotis and R. montanus in which the masseteric crest terminates below or ahead of the anterior root of m1. The pterygoid fossa is shallow and broad. The capsular process for the base of the incisor is not as pronounced as it is in Baiomys, and there is no groove above it.

A right dentary, 4394, is that of a more mature adult and is broken behind m2. The incisor width is 0. 5. The m1 and m2 resemble those in 4393 except that the anteroconid of m1 is slightly broader and the anterointernal valley is not as deep. No stylids are present. The anterolophid on m2 is poorly developed. The m1 is 1. 25 long and 0. 85 wide and m2 is 1. 05 long and 0. 85 wide. The diastema is 2. 0 long and 0. 8 wide, and the mental foramen is like that in 4393. The masseteric crest is weak and terminates below the anterior root of m1. The labial depth of the jaw below m1 is 2. 4.

A right dentary, 4395, of a young adult is broken across the diastema and behind m3. A portion of the incisor and m1-m3 are present. The incisor width below m1 is 0. 5. The jaw resembles Reithrodontomys in most respects but shows some similarities to Baiomys, the pygmy mice. The anteroconid of m1 is slightly more rounded anteriorly as in Baiomys and not as pointed as in R. montanus, but the distance across the protoconid-metaconid is narrower than in Baiomys kolbi from the Fox Canyon LF (Hibbard, 1952a). The anterointernal valley is shallow. A small mesostylid is present on m1 and an ectostylid is present on m1 and m2. The anterolophid of m2 is slightly better developed, as in some R. montanus, but there is no pit between it and the protoconid as there is in R. megalotis. The narrowness of the teeth, especially m2, resembles Reithrodontomys rather than Baiomys, in which m2 is more square. The posterior cingulum is well-developed in both m1 and m2. The m3 is

27triangular in outline, and the enamel wear pattern is S-shaped. The tooth is more reduced than in R. fulvescens but not as much as in R. megalotis or R. montanus. The anterolophid is narrow. The protoconid is well-developed and is separated from the metaconid by a shallow valley. The metaconid is shorter than in B. kolbi. The hypoconid is better developed than in either R. megalotis or R. montanus. The major fold is slightly longer than in either species but not as long as in R. fulvescens and extends nearly half way across the tooth. The primary fold is narrow, and the hypoconid and entoconid are fused. Measurements of the teeth in 4395 are: occlusal length of m1-m3 = 2. 95; occlusal length of m1-m2 = 2. 25; m1 = 1. 25 long by 0. 8 wide; m2 = 1. 0 long by 0. 8 wide; m3 = 0. 7 long by 0. 65 wide. The masseteric crest terminates ahead of the anterior root of m1 as in some R. montanus. The mental foramen is large and more labial than in the other specimens although, according to the late Claude W. Hibbard, this is somewhat variable in Baiomys. The labial jaw depth below m1 is 2. 3.

A left dentary fragment, 4396, of a young adult is broken behind m1. The m1 resembles that in 4393 in having a narrow pointed anteroconid and in lacking stylids. It is 1. 2 long and 0. 8 wide. The incisor is missing; minimum diastema width is 0. 7. The masseteric crest terminates below the anterior root of m1.

In the collection is a right maxillary fragment, 4397, of an adult bearing only the M1, which is 1. 45 long and 0. 9 wide. The anterocone is rounded and not bi-lobate. The paracone and protocone are alternating but the metacone lies opposite the hypocone. A weak anterolabial cingulum is present, and a small fourth root occurs medially on the labial side as in Reithrodontomys megalotis and R. montanus. The lower m1s of these species sometimes possess a small third root. Additional roots were not observed in the lower jaws from Red Corral.

Remarks. Remains of Reithrodontomys are rare in Blancan faunas. Four species have been described: R. wetmorei, R. rexroadensis, R. galushai, and R. pratincola. R. wetmorei and R. rexroadensis were described by Hibbard (1952a) from the early Blancan Fox Canyon LF of Meade County, Kansas. Their dentitions are generalized in comparison with recent forms, and their relationship to living species is uncertain. Some authors have suggested that the two species may be conspecific (Martin et al., 2003). Martin (written communication, 2015) expressed the opinion that R. rexroadensis (and Baiomys kolbi) are synonymous with R. wetmorei. As defined by Hibbard (1952a), R. wetmorei is the larger of the two species and is characterized by a wider tooth row, better development of a cingulum along the external edge of the anteroconid, and the presence of an ectostylid in the posteroexternal valley (major fold) of m2.

The Red Corral specimens are slightly smaller than most specimens assigned to Reithrodontomys rexroadensis with which they were compared but are tentatively referred to that species on the basis of similar size, a more pointed anteroconid, the absence of a prominent anterolabial cingulum, and the absence of stylids in three of the four dentaries.

It is possible that the Red Corral specimens belong to an undescribed species of Reithrodontomys or to R. galushai, another late Blancan species (see below), or that more than one taxon is represented. The late Claude W. Hibbard examined the specimens and agreed that those with narrow tooth rows, pointed anteroconids, and a weak capsular process (4393, 4396, and probably 4394) represent a small species of Reithrodontomys, whereas 4395 might equally represent a large species of Baiomys the size of the Blancan B. kolbi Hibbard or the extant B. musculus because of the rounded anteroconid on m1 and the slightly better anterolophid on m2.

According to Hibbard (1952a), Baiomys kolbi from the Fox Canyon LF is distinguished from Reithrodontomys rexroadensis by its smaller, less curved lower incisor, narrower diastema, broader and more rounded anteroconid on m1, better developed anterolophid on m2, less rectangular outline of m2, slightly larger m3, better developed capsular process, and shallower pterygoid fossa. Unfortunately, the diastemal portion of 4395 is broken, and the anterior part of the incisor as well as the capsular process and pterygoid fossa are missing. However, the width of the remaining part of the incisor is as great as in Reithrodontomys. The outline of m2 is rectangular, m3 is reduced and the anterolophid on m2 is no better developed than in some Holocene species of Reithrodontomys. For these reasons I am reluctant to assign 4395 to Baiomys and, in the absence of a larger sample including the more diagnostic M3 and m3 and showing the range of variation in tooth characters, I am reluctant to erect a new species of Reithrodontomys or to assign the Red Corral specimens to one of the Holocene species groups.

It also should be noted that Tomida (1987, p. 88) assigned a larger sample of teeth and jaw fragments from the early Blancan Duncan and late Blancan111 Ranch local faunas of southern Arizona to Reithrodontomys rexroadensis. His hypodigm includes upper teeth, although Hibbard (1952a) was reluctant to assign upper teeth to the species with any degree of confidence. A single M3 from the Duncan section shows an occlusal enamel pattern that is transitional between E-shaped and C-shaped (Hooper, 1952, p. 28). The three m3s show an enamel wear pattern that is S-shaped (Hooper, 1952, p. 29). These and certain other characters indicate, according to Tomida, that R. rexroadensis is transitional between the R. megalotis species group and the R. fulvescens species group of Hooper (1952), although Martin et al. (2003) consider the S-shaped morphology of m3 to be underived and of little value for higher taxonomic differentiation. If Tomida is correct in his assignment of the Arizona fossils to R. rexroadensis, the geographic range of the species (= R. wetmorei according to Martin) is extended to west of the Rocky Mountains and the geologic age from the early Blancan to the late Blancan (Tomida, 1987, p. 91). Tomida (1987, p. 92) also described a new species, R. galushai, from higher in the 111 Ranch section (late Blancan). He characterized it as being very similar to R. rexroadensis in size and general tooth morphology but differing from it in having m1 with a distinctly or indistinctly bilobed anteroconid and slightly narrower molars relative to the width but with a more rounded, conical metaconid and entoconid on m1 and m2. According to Tomida (1987, p. 39, table 23) the mean length of m1 in R. galushai (1. 36) is slightly greater than that of the Arizona sample of R. rexroadensis (1. 29) and the single m3 of R. galushai matches in size the larger of the m3s of R. rexroadensis. I have not had an opportunity to examine any of Tomida’s specimens but the size of the Red Corral molars falls within or close to the values given by Tomida for both species. The fourth Blancan species of Reithrodontomys, R. pratincola,

TABLE 8. Statistical summary of tooth measurements (in mm) of Onychomys cf. pedroensis from Red Corral Pits C and D. Abbreviations: L = length; Wtri = width of trigonid; Wtal = width of talonid.

Red Corral Pit CTooth Metric N OR Mean SD Tooth Metric N OR Mean SD

m1 L 9 1. 85-2. 05 1. 94 0. 058 M1 L 11 2. 0-2. 2 2. 09 0. 07

Wtri 10 0. 9-1. 1 1. 015 0. 058 W 11 1. 2-1. 4 1. 32 0. 065

Wtal 10 1. 1-1. 2 1. 18 0. 042 M2 L 4 1. 3-1. 5 1. 43 0. 096

m2 L 5 1. 5-1. 6 1. 54 0. 055 W 4 1. 1-1. 2 1. 18 0. 05

W 5 1. 2-1. 25 1. 24 0. 022

m3 L 1 1. 1 1. 1W 1 1. 3 1. 3

Red Corral Pit D

M1 L 5 1. 7-2. 2 1. 94 0. 195

W 5 1. 1-1. 35 1. 21 0. 114

M2 L 2 1. 5-1. 6 1. 55

W 2 1. 2 1. 2

from the latest Blancan Borchers LF, Meade County, Kansas, is smaller than the Red Corral species and the single m3 in the right dentary, KU 6466, is reduced and has a C-shaped occlusal pattern according to the illustration in Hibbard (1942, pl. 1, fig. 11). The same is true for R. moorei from the Irvingtonian age Cudahy Fauna of Kansas (Paulson, 1961).

Clearly, the genus Reithrodontomys is in need of revision. Any such revision should involve a comparison with small species of Peromyscus and with species of Baiomys.

Onychomys cf. pedroensis Gidley, 1922Figure 20D

Referred specimens. Pit C; 4398, left dentary fragment with m2 and m3; 4399, edentulous right dentary fragment; 4400, edentulous right dentary fragment; 4401, isolated lower teeth including 10 m1s;

284402, left maxillary fragment with M1; 4403, isolated upper teeth. Pit D: 4044, isolated teeth.

Description. A left dentary fragment, 4398, of a grasshopper mouse is broken just anterior to m2 and is missing the posterior processes. The m2 and m3 indicate a mature adult in wear stage III or IV of Carleton and Eshelman (1979). The m2 contains broad folds that lack accessory cusps or cingula. The m3 has a narrower talonid and is more triangular in outline than in specimens of Onychomys gidleyi with which it was compared. Measurements of m2 are: length = 1. 5; width = 1. 2. Measurements of m3 are: length = 1. 1; talonid length = 0. 5; talonid width = 1. 0. A broad, shallow valley separates m3 from the ascending ramus.

Among the isolated lower teeth, 4401, from Pit C are 10 m1s in different wear stages. Cingula are weak or absent. One tooth possesses a prominent mesostylid. Three teeth possess a vestigial bud for a third root. Measurement summaries of the m1s as well as five m2s and a single m3 are given in Table 8.

The upper teeth, 4402 (Fig. 20D) and 4403, from Pit C include 11 M1s. Mesostyles and cingula are present on some of the teeth. Measurement summaries of the M1s including five M1s, 4044, from Pit D are given in Table 8. Six M1s (43 %) of the combined sample possess a tiny fourth root or nub beneath the paracone.

Remarks. Measurements of the lower teeth from the Red Corral LF were compared with those of Onychomys gidleyi (early Blancan) and O. pedroensis (late Blancan-early Irvingtonian) given by Carleton and Eshelman (1979). The average length of m1 and m2 exceeds the length of most O. gidleyi except the larger specimens from the Fox Canyon LF but falls within the range of O. pedroensis from the Borchers and Curtis Ranch local faunas of Kansas and Arizona, respectively. However, the width of m1 and m2 as well as the length and width of the single m3 from Red Corral fall within the range of both species, although more like O. pedroensis because of the smaller, reduced talonid on m3. The Red Corral specimens are larger than O. bensoni from Arizona and O. hollisteri, including the teeth from the Deer Park B LF of Kansas referred to the latter by Martin et al. (2002b).

Carleton and Eshelman (1979), using mandibles, demonstrated an evolutionary increase in length of the first and second molars at the expense of the third molar in Onychomys. Unfortunately, the limited material from Red Corral precludes such comparisons with one exception. The ratio of the length of m3 to that of m2 in 4398 is 0. 73:1. 0, which matches most closely to that of O. pedroensis. A larger and better sample is needed to determine whether the Red Corral grasshopper mouse actually represents O. gidleyi, O. pedroensis, or an intermediate grade on the lineage leading to O. leucogaster as shown by Carleton and Eshelman (1979, p. 28).

Bensonomys cf. arizonae (Gidley, 1922)Figures 20E-F

Referred specimens. Pit C: 4370-4377, eight tooth-bearing right dentaries and dentary fragments; 4379, isolated m1s; 4380-4386, four left and three right maxillary fragments; 4387, isolated M1s. Pit D: 4037, right dentary with incisor, m1-m3; 4038, left dentary fragment with m1-m2; 4142, associated right and left lower dentitions; 4143, left dentary with m1-m2; 4144, isolated teeth.

Description. This cricetine rodent is well represented in the fauna by 11 tooth-bearing dentaries or dentary fragments, seven maxillary fragments, and a number of isolated teeth. A right dentary, 4370, of an adult contains the incisor and m1-m3, the angular process and part of the coronoid process but is broken just anterior to the mental foramen. A knob-like process occurs at the anterior extremity of the masseteric crest, and the mental foramen is dorsally placed on the diastema just above this process and just in front of the anterior root of m1. There is a shallow sulcus above the capsular process for the incisor. A small foramen occurs in the depression between m3 and the ascending ramus. Labial jaw depth below m1 is 3. 2. The anteroconid on m1 is divided by a shallow anteromedial groove, with the labial conulid slightly larger than the lingual one. The protoconid and hypoconid are low, broad, and V-shaped with the V pointing posterolabially. The labial valleys are open and broad, and a wide cingulum extends from the anteroconid back to the protoconid and across the labial reentrant. The metaconid is widely separated from the anteroconid by a broad valley. There is a third rootlet present. The m2 is sub rectangular with the anterior end wider than the posterior. The valleys are broad, and the anterior and labial cingula are well-developed. The m3 tapers posteriorly but is not reduced. The anterior and labial cingula are slightly developed. The greatest length of m1-m3 is 3. 9, and the length of m1-m2 is 2. 9. The

incisor width is 0. 5. A right dentary, 4371, of a young adult contains the incisor,

diastema, and m1-m3 but is broken posterior to m3. The diastema is 2. 6 long. The mental foramen is placed as in 4370, but the knob-like process is slightly more posterior and lies below the anterior root of m1 rather than ahead of it. A small foramen occurs between m3 and the ascending ramus. Labial jaw depth below m1 is 3. 4 and below the mental foramen is 2. 2. Compared with 4370, the teeth are less worn. The anteroconid of m1 is bilobate but with a small anterostylid in the anteromedial groove. The connection between the anteroconid and the protoconid and hypoconid is narrower due to less wear, thus giving the former a “bow tie” appearance. The m2 is squarer, and the labial cingula in both m1 and m2 are less developed. The m3 shows an S-shaped pattern with the entoconid and hypoconid broadly confluent. There is no third root on m1. The greatest length of m1-m3 is 3. 7, and the length of m1-m2 is 2. 8. The incisor width is 0. 6.

A right dentary fragment, 4372, belongs to an old adult. The diastema is 2. 5 long and the labial jaw depth below m1 is 3. 7 and below the mental foramen is 2. 3. Incisor width is 0. 6. Greatest length of m1-m2, which are heavily worn, is 2. 85. There is a small third root on the labial side of m1

The remaining dentary fragments and isolated m1s from Pit C show only minor variations and are like those described above. Most m1s have well-developed labial cingula. The shape of m1 varies with the width of the anteroconid and development of the anteromedial groove. All but one specimen possess a bilobate anteroconid with equally developed conulids. In 4374, this cusp is narrow and undivided but still separated from the other cusps by wide valleys, and the tooth appears triangular and more pointed anteriorly than the others. The presence or absence of an anterostylid in the anteromedial groove and of a third root on m1 is variable. The mean length and width of all 11 m1s (isolated and in jaws) from Pit C are 1. 60 (OR = 1. 5-1. 7; SD = 0. 061) and 1. 06 (OR = 1. 0-1. 15; SD = 0. 055), respectively.

The dentaries from Pit C compare favorably in size and general morphology with a series of six dentaries (UMMP 29675) of Bensonomys eliasi from Rexroad Locality 3, Kansas, in the University of Michigan collections and with a paratype dentary, KU 4547, at the University of Kansas. The holotype, KU 3941, has teeth too worn for adequate comparison. The Pit C jaws are larger than the holotype of B. meadensis from the Sanders LF (Hibbard, 1956) or the holotype of B. arizonae from the Benson LF (Gidley, 1922; Gazin, 1942) but individual tooth measurements overlap in size with teeth assigned to B. eliasi from Rexroad Locality 3 and B. meadensis from Deer Park B, Kansas, by Martin et al. (2002b) and teeth assigned to B. arizonae from the early Blancan Verde LF, Arizona,by Czaplewski (1987a) and the 111 Ranch LF, Arizona, by Tomida (1987).

Three dentaries from Pit D are similar to those from Pit C but are slightly smaller. Specimens 4037 and 4038 are a right and left dentary that show identical tooth wear pattern and preservation and probably belong to a single young adult. The right dentary, 4037, is more complete and contains the incisor and m1-m3 but is broken across the diastema and posterior to m3 (Fig. 20E). The knob-like process on the masseteric crest turns upward; the mental foramen is dorsally situated on the diastema ahead of m1. There is a shallow sulcus above the capsular process and a small foramen between m3 and the base of the ascending ramus. Labial jaw depth below m1 is 3. 3 and below the mental foramen is 2. 4. The anterior face of m1 is blunt, and the anteroconid is bilobate. Labial cingula are moderately developed on m1 and m2. The m3 is more reduced posteriorly. The greatest length of m1-m3 is 3. 6 (m1 = 1. 5 x 1. 0; m2 = 1. 15 x 1. 0; m3 = 1. 0 x 0. 9). Incisor width is 0. 55.

A left dentary, 4143, of a young adult contains m1-m2 but lacks the incisor (Fig. 20F). The diastema is 2. 5 long. The anteroconid on m1 is inflated anteriorly but is not bilobate. Labial cingula are well-developed. Length of m1-m2 is 2. 6 (m1 = 1. 45 x 1. 0; m2 = 1. 15 x 1. 0).

No. 4142 consists of associated complete right and left lower dentitions including incisors of a young adult; most of the jaw bone has deteriorated. Measurements are: m1 = 1. 6 x 1. 0; m2 = 1. 15 x 1. 0; m3 = 1. 0 x 0. 8. The m1 is two-rooted. The incisor width is 0. 5. Additional measurements of lower teeth and jaws from both Pit C and Pit D are summarized in Table 9 along with those of teeth from the Rexroad 3 and Deer Park B local faunas of Kansas and the Verde and 111 Ranch local faunas of Arizona.

Associated with the dentaries at Pit C are seven tooth-bearing maxillary fragments and eight isolated M1s in various wear stages.

29TABLE 9. Statistical summary of jaw and tooth measurements (in mm) of Bensonomys cf. arizonae from Red Corral Pits C and D and faunas in Kansas and Arizona. Abbreviations: L = length; W = width; Occl. = occlusal; Ld = labial jaw depth; mf = mental foramen.

Pit C Pit CTooth Measure N OR Mean SD Tooth Measure N OR Mean SD

m1 L 11 1. 5-1. 7 1. 6 0. 061 M1 L 14 1. 6-1. 8 1. 71 0. 068W 11 1. 0-1. 15 1. 06 0. 055 W 14 1. 0-1. 15 1. 07 0. 054

m2 L 3 1. 15-1. 25 1. 2 M2 L 2 1. 2-1. 3 1. 25W 3 0. 95-1. 1 1. 02 W 2 1 1

m3 L 2 1 1W 2 0. 8 0. 8

m1-m3 Occl. L 2 3. 7-3. 9 3. 8m1-m2 Occl. L 3 2. 8-2. 9 2. 85

Jaw Ld mf 3 2. 2-2. 3 2. 27Jaw Ld m1 4 3. 2-3. 7 3. 45

Pit DTooth Measure N OR Mean Tooth Measure N OR Mean

m1 L 4 1. 45-1. 6 1. 51 M1 L 2 1. 8 1. 8W 4 1 1 W 2 1. 1 1. 1

m2 L 4 1. 15 1. 15W 4 1 1

m3 L 2 1 1W 2 0. 8-0. 9 0. 85

m1-m3 Occl. L. 2 3. 6-3. 7 3. 65m1-m2 Occl. L. 4 2. 6-2. 75 2. 66

Jaw Ld mf 1 2. 4 2. 4Jaw Ld m1 1 3. 3 3. 3

Bensonomys eliasi from Rexroad Locality 3, Kansas. Measurements by author. Tooth Measure N OR Mean SD

m1 L 23 1. 5-1.7 1. 59 0. 05W 24 0. 9-1. 1 1. 02 0. 449

m2 L 16 1. 1-1. 2 1. 17 0. 043W 16 0. 95-1. 1 1. 04 0. 038

m3 L 8 1. 0-1. 1 1. 02 0. 035W 8 0. 8-0. 9 0. 88 0. 035

m1-m3 Occl. L 7 3. 7-3. 9 3. 79 0. 068m1-m2 Occl. L 15 2. 6-2. 9 2. 76 0. 86

Bensonomys meadensis from Deer Park B, Kansas. Measurements from Martin et al (2000b). Tooth Measure N OR Mean Tooth Measure N OR Mean

m1 L 3 1. 55-1. 6 1. 58 M1 L 2 1. 62-1. 65W 3 0. 95-1. 02 0. 98 W 2 0. 99-1. 02

m2 L 2 1. 23-1. 24 M2 L 3 1. 12-1. 18 1. 14W 3 0. 98-1. 09 1. 04 W 3 0. 88-0. 96 0. 92

Bensonomys arizonae from Verde LF, House Mtn., Arizona. Measurements from Czaplewski (1987a). Tooth Measure N OR Mean Tooth Measure N OR Mean

m1 L 7 1. 54-1. 71 1. 59 M1 L 3 1. 61-1. 69 1. 66W 6 1. 06-1. 16 1. 12 W 3 1. 08-1. 18 1. 13

m2 L 3 1. 13-1. 21 1. 17 M2 L 6 1. 14-1. 23 1. 19W 3 1. 03-1. 15 1. 08 W 6 0. 98-1. 07 1. 04

m3 L 2 1. 04-1. 05 1. 04 M3 L 4 0. 8-0. 9 0. 85W 2 0. 9-0. 92 0. 91 W 4 0. 83-0. 89 0. 87

m1-m3 Occl. L 2 3. 86-4. 12 3. 99Bensonomys arizonae from 111 Ranch, Arizona. Measurements from Tomida (1987).

Tooth Measure N OR Mean Tooth Measure N OR Meanm1 L 2 1. 54-1. 62 1. 58 M1 L 3 1. 52-1. 6 1. 57

W 2 0. 96-1. 06 1. 01 W 3 1. 02-1. 06 1. 04m2 L 3 1. 12-1. 20 1. 15 M2 L 1 1. 12

W 3 0. 96-1. 08 1. 02 W 1 0. 92m3 L 4 0. 96-1. 04 1. 01 M3 L 1 0. 82

W 4 0. 76-0. 88 0. 82 W 1 0. 78m1-m3 Occl. L 1 3. 92

30The anterocone is generally broad and divided anteromedially into two equal or sub-equal conules. Labial cingula are weakly to strongly developed, and several M1s possess an anterocingulum at the base of the anterocone. In some teeth, accessory cusps (mesostyles) are present in the labial reentrant valleys, especially the first. A fourth labial root is weakly developed in over 50 % of the M1s. M1-M2 length in two specimens is 2. 85 and 2. 9. The mean length and width of 14 M1s (isolated and in max. fragments) from Pit C are 1. 71 (OR = 1. 6-1. 8; SD = 0. 068) and 1. 07 (OR = 1. 0-1. 15; SD = 0. 054), respectively. Additional upper tooth measurements are summarized in Table 9.

Remarks. The taxonomic history of Bensonomys is complex. Eligmodontia arizonae Gidley, 1922 from the Blancan age Benson LF of Arizona became the type species of the genus Bensonomys (Gazin, 1942). Gazin, however, noted many similarities between the extinct North American genus and the Quaternary South American phyllotine Eligmodontia.

Hibbard (1938) named Peromyscus eliasi from the Rexroad Locality 3 LF, Meade County, Kansas on the basis of a dentary with much worn teeth and later (Hibbard, 1941c) referred additional material from the same fauna to Eligmodontia? arizonae. In 1950, he synonymized P. eliasi and E. ? arizonae with Bensonomys arizonae and assigned to that species a series of dentaries from the Fox Canyon LF in Meade County, which, he noted, were larger than the holotype and showed considerable variation in enamel pattern and size (Hibbard, 1950). In 1956, he recognized B. eliasi as a valid species to which he referred both the Rexroad and Fox Canyon forms and also described a smaller species, B. meadensis, from the Sanders LF also in Meade County (Hibbard, 1956). Earlier, Hibbard (1953b) described Cimarronomys stirtoni from the earliest Blancan Saw Rock Canyon LF in Meade County. This species was later included as a species of Bensonomys (Baskin, 1978) and, more recently, listed as a species of Symmetrodontomys (Martin et al., 2008; Martin and Peláez-Campomanes, 2014).

Baskin (1978) considered there to be a close relationship between Eligmodontia and Bensonomys and made the latter a subgenus of Calomys, another South American phyllotine. He noted that Calomys differs from Eligmodontia in having more brachydont teeth and a more bifurcated anterocone (-id), and that the absence of super numerary roots in teeth of Calomys (Bensonomys) is not a consistent and diagnostic characteristic as Hibbard (Skinner et al., 1972) had thought since extra roots may be present in some species. He also described a small species, C. (B. ) yazhi, and a larger species, C. (B. ) gidleyi, from the late Hemphillian White Cone LF, Bidahochi Formation, Arizona, and reviewed the evolutionary and zoogeographic history of the genus. Dalquest (1983) described C. (B. ) coffeyi from the late Hemphillian Coffee Ranch LF, Hemphill County, Texas. Lindsay and Jacobs (1985) described a small species, C. (B. ) elachys, and a large species, C. (B. ) baskini, from the late Hemphillian Yepomera and early Blancan Concha local faunas, Chihuahua, Mexico. Carranza-Castañeda and Walton (1992) described C. (B. ) winklerorum from the latest Hemphillian or earliest Blancan El Cote Fauna, Guanajuato, Mexico. Martin et al. (2002b) considered Bensonomys to be a primitive phyllotine closely related to Calomys but, because of its plesiomorphic features, they opted to return Bensonomys to generic status. Martin et al. (2002a) described B. hershkovitzi from the late Hemphillian Pipe Creek Sinkhole, Grant County, Indiana. Kelly (2007) reviewed the systematic history of Bensonomys and described B. lindsayi from the early late Hemphillian Coal Valley Formation of Smith Valley, Nevada.

To date, a total of 12 species of Bensonomys have been described in the literature making detailed comparisons difficult. Future work may show some of these to be conspecific. Lindsay and Jacobs (1985) stated that Calomys (Bensonomys) elachys is a small species about the size of C. (B. ) yazhi whereas C. (B. ) baskini is about the size of C. (B. ) stirtoni. According to Tomida (1987, p. 96), C. (B. ) stirtoni and C. (B. ) baskini are much larger than C. (B. ) arizonae, the genotypic species, whereas C. (B. ) yazhi, and C. (B. ) gidleyi are smaller than C. (B. ) arizonae. C. (B. ) yazhi also differs from the latter by having a better developed posterior cingulum on M1 and by having three-rooted m2 and m3. C. (B. ) gidleyi also differs from C. (B. ) arizonae by having a mesoloph on M1. Czaplewski (1987a) gave further comparisons with C. (B. ) arizonae and also commented that C. (B. ) coffeyi is the same size as C. (B. ) arizonae but that Dalquest’s diagnosis could be applied to almost any species of C. (Bensonomys). Carranza-Castañeda and Walton (1992, p. 76) diagnosed C. (B. ) winklerorum as follows: “M1 has sub equally bilobed anterocone with a moderately deep anteromedian groove; m1 bilobed only in earliest stages of wear. Tendency to retain short, narrow mesoloph on M1, no auxiliary lophs

or lophids in other teeth. M3s large. Size intermediate between that of Calomys baskini and Calomys elachys/Baiomys kolbi. ” They noted comparisons with other species of the genus including C. (B. ) arizonae. They stated (p. 76) that Calomys arizonae from the early Blancan Verde Formation of Arizona, strongly resembles C. winklerorum in size and essential features but that it is higher-crowned, to the extent that the m1 anteroconid remains bilobed with moderate wear, and has no accessory lophs or lophids. According to Martin et al. (2002a), B. hershkovitzi differs from all other species of the genus in having a long and narrow dentine field of labial anterior cingulum connected to the dentine field of anteroconid in minimal wear and by the presence of a mesolophid on m1. Kelly (2007, p. 126) gave a lengthy diagnosis of B. lindsayi and a lengthy and detailed comparison with other species in terms of size and morphological features that will not be repeated here.

Comparison of the Red Corral Bensonomys with the known Blancan species is more relevant to this paper. Hibbard (1956) distinguished Bensonomys eliasi from the similar-sized B. arizonae on the basis of a wider lower incisor, an m1 that is more rectangular with a broad versus triangular anteroconid, and broader reentrant valleys in m1 and m2. He distinguished Bensonomys meadensis from B. eliasi by its smaller size and narrower lower incisor. He differentiated B. meadensis from B. arizonae by the position of the masseteric crest. The anterior end of the masseteric crest in B. meadensis is said to be more dorsal and more posterior to the mental foramen. He considered both B. meadensis and B. arizonae to have similar shaped m1s, with a rectangular-shaped anteroconid, in contrast to the broad anteroconid he attributed to B. eliasi. However, Czaplewski (1987a) stated that, in the absence of quantified differences and comparative specimens, he could not distinguish specimens from the Verde Formation of Arizona that he assigned to B. arizonae from the other two species. Martin et al. (2002b) assigned a sample of teeth from Deer Park B to B. meadensis. Martin et al. (2008) and Martin and Peláez-Campomanes (2014) continued to recognize the Fox Canyon species as B. eliasi but assigned the Rexroad 3 fossils to B. meadensis while continuing to recognize the Deer Park and Sanders specimens as belonging to the latter species.

The Red Corral specimens from Pit C compare favorably in size and morphology with specimens from Rexroad Locality 3 and Deer Park B whereas some of the specimens from Pit D are smaller and compare better in size with B. meadensis. However, there is considerable overlap in size between teeth from Rexroad Locality 3 and Deer Park B and teeth assigned to B. arizonae from the Verde and 111 Ranch local faunas of Arizona (Table 9). Martin (written communication, 2015) indicated that many of the features used by Hibbard to separate these three species are highly variable and that B. arizonae, B. eliasi, and B. meadensis may be conspecific. He suggested that the Red Corral specimens be assigned to B. arizonae, the earliest named of the three species and I have followed his suggestion.

Sigmodon minor /medius Gidley, 1922Figure 21E

Referred specimens. Pit C: 4404-4419, 16 tooth-bearing left dentaries and dentary fragments; 4420-4428, 9 tooth-bearing right dentaries and dentary fragments; 4378, two edentulous left dentary fragments; 4429-4441, 13 tooth-bearing left maxillary fragments; 4442-4455, 14 tooth-bearing right maxillary fragments; 4456, isolated teeth. Pit D: 4048-4057, 4072-4077, 4146-4157, 28 tooth-bearing left dentaries and dentary fragments; 4058-4071, 4158-4171; 4187-4192, 34 tooth-bearing right dentaries and dentary fragments; 4078, edentulous dentary fragments; 4079-4084, 4193-4194, eight left maxillary fragments with M1-M3; 4085, 4195-4197, four right maxillary fragments with M1-M3; 4086, edentulous maxillary fragments; 4087, isolated teeth.

Description. This small and primitive cotton rat is by far the most abundant taxon in the Red Corral LF at both Pits C and D (Fig. 21E). A total of 12 tons of matrix was screen washed from Pit C and 28 tons from Pit D. Based on a count of lower m1s obtained, the minimum number of individuals from Pit C is 40 (40 left m1s and 38 right m1s) and from Pit D is 139 (120 left m1s and 139 right m1s). The large sample size permits a statistical analysis of both upper and lower molars and allows comparisons with samples of this taxon from other Blancan faunas in the Southern High Plains and the southwestern United States. Tooth morphology of the Red Corral cotton rat is consistent with that given by R. A. Martin (1979) in his emended diagnosis of the medius species group of Sigmodon and also with that given by Tomida (1987). Martin notes that relative to all other Sigmodon species, the dentition is brachydont and that reentrant folds on all teeth are relatively

31

FIGURE 21. Neotoma (Paraneotoma) cf. fossilis: A, both maxillaries, M1-M2, 4457, Pit C; B, left maxillary, M1-M2, 4458, Pit C; C, associated left and right m1-m3, 4045, Pit D; D, right m1, 4047, Pit D. Sigmodon minor /medius: E, left dentary with incisor, m1-m3, 4048, Pit D.

shallow. Tomida (1987, p. 98) further states that “cusps of cheek teeth are anteroposteriorly compressesd and lophate; cusps of upper teeth slope slightly anteriorly, whereas cusps of lower teeth slope slightly posteriorly. Cusps and lophs are relatively inflated almost robust, and correspondingly the flexa and flexids are relatively deep and narrow. ”A well-developed anterior cingulum is present on m2 and m3. Detailed morphologies of each molar are given by Tomida (1987) and are not repeated here. Measurement summaries of the Red Corral molars are given in Table 10. As mentioned above, greatest length and width of the teeth were measured to the nearest 0. 05 mm using an ocular grid in a binocular microscope and viewing the teeth perpendicular to the occlusal surface. Although immature tooth caps and extremely worn or weathered teeth were excluded from the measurement sample, it is possible that the measured length of some teeth is biased by about 0. 1 mm longer because of the cusp inflation and the anterior or posterior slope of the teeth mentioned by Tomida. The tooth dimensions of the Pit C and Pit D samples are very similar. The mean dimensions of the lower molars from Pit D range from 0. 00 to 0. 06 greater than those from Pit C. The mean dimensions of the upper molars from both sites are nearly identical. Table 10 also gives tooth measurements of specimens collected from Rexroad Locality 3 and other localities in the Meade Basin of Kansas as well as from several Blancan local faunas in Arizona. Data come from Peláez-Campomanes and Martin (2005), Czaplewski (1987a), and Tomida (1987). Compared with the Rexroad 3 sample, the mean length of the lower m1 and m2 in the Red Corral sample is 6 to 11 % greater, although the mean length of the lower m3 is 5 to 7 % shorter. Mean width of the lower m1 and m2 in the Red Corral sample, however, is 3 to 6 % shorter. Dimensions of the upper M1 and M2 vary from 2 % shorter to 5 % greater. The Red Corral M3 is 8 %

longer and 4 to 6 % narrower than that of the Rexroad sample. Molars in the Wendell Fox sample are larger than those in the Red Corral samples in nearly all dimensions. There is also variation within and between the Arizona samples. In sum, the large size of the Red Corral samples will permit additional statistical analyses and comparisons to be made beyond those attempted in this paper.

The lower m1 of Sigmodon minor /medius is characterized by two well-developed roots – one anterior and one posterior. In addition, one or two accessory rootlets may be present between them as tiny pegs. When one rootlet is present it is usually in a labial position but it may occur rarely in a medial position. In rare instances, two accessory rootlets may be present – one labial and the other lingual. In many instances the position of an accessory rootlet is marked by only a slight bump. Hibbard in Skinner et al. (1972) emphasized the taxonomic utility of dental root morphology, particularly within the genus Sigmodon. At present, only the lower m1 appears to have extensive taxonomic utility with regard to the development of accessory rootlets (Martin, 1979). In a sample of 62 lower m1s from Red Corral Pit C, four (6. 5 %) have two accessory rootlets, 24 (39 %) have one accessory rootlet (22 labial and two medial in position), seven (11 %) have a slight “bump”, and 27 (43. 5 %) have no accessory rootlet. In a sample of 156 lower m1s from Red Corral Pit D, six (4 %) have two accessory rootlets, 73 (47 %) have one accessory rootlet (64 labial and nine medial in position), 17 (11 %) have a slight bump, and 60 (38. 5 %) have no accessory rootlet.

Accessory rootlets may be present occasionally in the upper M1s. In a sample of 130 upper M1s from Red Corral Pit D, six (4. 6 %) possess a tiny accessory rootlet labially between two of the three major roots. A tiny bump is present in this position in 11 % of both the Pit C and Pit D samples.

32TABLE 10. Statistical summary of tooth measurements (in mm) of Sigmodon minor/medius from Red Corral Pits C and D and other Blancan local faunas. Abbreviations: L = length; W = width; alv. = alveolar

Red Corral Pit CTooth Measure N OR Mean SD Tooth Measure N OR Mean SD

m1 L 75 1. 9-2. 5 2. 2 0. 12 M1 L 78 1. 8-2. 5 2. 12 0. 127W 75 1. 2-1. 55 1. 35 0. 077 W 78 1. 4-1. 9 1. 63 0. 115

m2 L 58 1. 5-2. 0 1. 66 0. 101 M2 L 60 1. 4-2. 0 1. 61 0. 118W 58 1. 3-1. 75 1. 49 0. 094 W 60 1. 3-1. 9 1. 55 0. 113

m3 L 5 1. 5-2. 1 1. 8 0. 136 M3 L 48 1. 3-1. 7 1. 49 0. 084W 5 1. 3-1. 7 1. 46 0. 098 W 48 1. 2-1. 7 1. 37 0. 099

m1-m3 L 4 5. 1-5. 55 5. 3 0. 212 M1-M3 L 0

m1-m2 L 8 3. 3-4. 15 3. 71 0. 256

m1-m3 L alv. 2 5. 2-5. 9 5. 55Red Corral Pit D

m1 L 252 2. 0-2. 5 2. 26 0. 105 M1 L 217 1. 7-2. 5 2. 12 0. 139W 252 1. 0-1. 55 1. 38 0. 07 W 217 1. 2-1. 9 1. 61 0. 111

m2 L 206 1. 4-2. 0 1. 72 0. 108 M2 L 149 1. 3-1. 9 1. 59 0. 11W 206 1. 1-1. 8 1. 52 0. 093 W 149 1. 2-1. 8 1. 58 0. 111

m3 L 125 1. 5-2. 2 1. 84 0. 139 M3 L 111 1. 3-1. 7 1. 5 0. 1W 125 1. 2-1. 7 1. 46 0. 092 W 111 1. 1-1. 6 1. 39 0. 107

m1-m3 L 28 5. 2-6. 0 5. 56 0. 214 M1-M3 L 12 5. 0-5. 7 5. 2 0. 25

m1-m2 L 50 3. 6-4. 2 3. 86 0. 158

m1-m3 L alv. 19 5. 2-6. 0 5. 68 0. 243All Kansas data after Peláez-Campomanes and Martin (2005) Rexroad Loc. 3A, Kansas Rexroad Loc. 3B, Kansas

Tooth Measure N OR Mean SD Tooth Measure N OR Mean SDm1 L 39 1. 75-2. 36 2. 03 0. 122 M1 L 3 1. 97-2. 30 2. 17

W 41 1. 27-1. 65 1. 43 0. 073 W 3 1. 51-1. 65 1. 56

m2 L 23 1. 33-1. 81 1. 56 0. 096 M2 L 3 1. 50-1. 59 1. 54W 23 1. 39-1. 68 1. 56 0. 07 W 3 1. 53-1. 61 1. 57

m3 L 15 1. 75-2. 14 1. 93 0. 115 M3 L 1 1. 39W 15 1. 34-1. 64 1. 48 0. 077 W 1 1. 45

Wendell Fox Pasture, Kansasm1 L 8 2. 07-2. 34 2. 24 0. 087 M1 L 6 2. 19-2. 53 2. 31 0. 138

W 9 1. 41-1. 59 1. 5 0. 061 W 6 1. 66-1. 97 1. 8 0. 112

m2 L 8 1. 52-1. 85 1. 72 0. 106 M2 L 3 1. 56-1. 96 1. 77W 8 1. 51-1. 75 1. 62 0. 077 W 3 1. 85-1. 97 1. 89

m3 L 2 1. 89-1. 92 1. 91W 2 1. 50-1. 68 1. 59

Deer Park, Kansasm1 L 7 1. 91-2. 08 1. 98 0. 061 M1 L 8 1. 96-2. 33 2. 16 0. 135

W 13 1. 23-1. 56 1. 38 0. 098 W 8 1. 54-1. 85 1. 67 0. 124

m2 L 7 1. 31-1. 61 1. 51 0. 106 M2 L 4 1. 40-1. 50 1. 44W 7 1. 45-1. 61 1. 55 0. 061 W 4 1. 38-1. 64 1. 52

m3 L 7 1. 61-1. 95 1. 79 0. 152 M3 L 4 1. 39-1. 57 1. 48W 7 1. 33-1. 56 1. 48 0. 081 W 4 1. 23-1. 61 1. 45

Sanders 2, Kansasm1 L 9 1. 94-2. 14 2. 04 0. 095

W 10 1. 21-1. 50 1. 41 0. 085

m2 L 8 1. 40-1. 69 1. 54 0. 085W 8 1. 53-1. 68 1. 6 0. 052

m3 L 6 1. 88-2. 14 1. 96 0. 1W 6 1. 44-1. 64 1. 54 0. 072

33Tusker LF Loc. 15-24 111 Ranch, Arizona (after Tomida, 1987)

Tooth Measure N OR Mean SD Tooth Measure N OR Mean SDm1 L 121 1. 84-2. 28 2. 03 0. 093 M1 L 113 1. 80-2. 28 2. 04 0. 102

W 139 1. 28-1. 60 1. 41 0. 063 W 121 1. 36-1. 80 1. 59 0. 092

m2 L 149 1. 40-1. 68 1. 55 0. 066 M2 L 94 1. 32-1. 64 1. 44 0. 064W 150 1. 36-1. 68 1. 55 0. 064 W 96 1. 36-1. 92 1. 58 0. 094

m3 L 92 1. 52-2. 08 1. 79 0. 118 M3 L 46 1. 28-1. 60 1. 43 0. 094W 93 1. 32-1. 72 1. 48 0. 083 W 45 1. 20-1. 52 1. 37 0. 074

m1-m3 L 25 5. 31-5. 94 5. 64 0. 176 M1-M3 L 9 4. 75-5. 75 5. 43 0. 278Duncan LF Loc. 7937, Arizona (after Tomida, 1987)

m1 L 6 2. 00-2. 28 2. 13 0. 106 M1 L 12 2. 00-2. 24 2. 11 0. 075W 6 1. 32-1. 52 1. 44 0. 084 W 12 1. 60-1. 72 1. 67 0. 033

m2 L 7 1. 48-1. 64 1. 54 0. 06 M2 L 14 1. 44-1. 56 1. 52 0. 039W 7 1. 40-1. 60 1. 54 0. 083 W 13 1. 48-1. 72 1. 61 0. 062

m3 L 10 1. 52-1. 96 1. 82 0. 131 M3 L 14 1. 36-1. 60 1. 49 0. 071W 10 1. 28-1. 60 1. 51 0. 1 W 14 1. 28-1. 56 1. 48 0. 074

m1-m3 L 2 5. 67-5. 92 5. 8Verde LF. Arizona (after Czaplewski, 1990)

m1 L 4 1. 98-2. 37 2. 24 M1 L 5 1. 74-2. 23 2. 1W 4 1. 30-1. 51 1. 45 W 5 1. 51-1. 77 1. 67

m2 L 5 1. 70-1. 93 1. 82 M2 L 5 1. 63-1. 80 1. 73W 6 1. 54-1. 69 1. 64 W 5 1. 57-1. 84 1. 71

m3 L 2 2. 10-2. 26 2. 18 M3 L 5 1. 34-1. 56 1. 49W 3 1. 43-1. 67 1. 57 W 5 1. 44-1. 61 1. 55

m1-m3 L 2 6. 20-6. 33 6. 26 M1-M3 L 1 5. 3Borchers LF, Kansas

Tooth Measure N OR Mean SD Tooth Measure N OR Mean SDm1 L 49 1. 72-2. 22 1. 92 0. 127 M1 L 14 1. 80-2. 40 2. 14 0. 153

W 51 1. 14-1. 48 1. 29 0. 076 W 15 1. 35-1. 63 1. 5 0. 079

m2 L 56 1. 22-1. 78 1. 42 0. 12 M2 L 14 1. 25-1. 75 1. 5 0. 124W 54 1. 20-1. 55 1. 41 0. 078 W 14 1. 19-1. 63 1. 5 0. 126

m3 L 32 1. 40-1. 84 1. 66 0. 12 M3 L 8 1. 23-1. 57 1. 38 0. 099W 30 1. 20-1. 50 1. 34 0. 075 W 8 1. 18-1. 43 1. 31 0. 088

UA Loc. 25-3 Curtis Ranch, Arizona (after Tomida, 1987)m1 L 4 1. 88-2. 12 1. 99 0. 1 M1 L 8 1. 88-2. 04 1. 99 0. 06

W 5 1. 28-1. 36 1. 32 0. 04 W 8 1. 48-1. 60 1. 52 0. 043

m2 L 5 1. 24-1. 44 1. 34 0. 092 M2 L 6 1. 20-1. 40 1. 31 0. 07W 6 1. 32-1. 52 1. 44 0. 08 W 6 1. 28-1. 52 1. 44 0. 091

m3 L 3 1. 56-1. 68 1. 63 M3 L 2 1. 24-1. 36 1. 3W 3 1. 28-1. 44 1. 35 W 2 1. 20-1. 40 1. 3

m1-m3 L 3 5. 08-5. 50 5. 36 M1-M3 L 1 5. 42

Accessory rootlet data for a sample of lower m1s from the Rexroad Locality 3 LF are provided by Martin (1979). Similar data for both upper and lower first molars in several Blancan faunas in Arizona are given by Tomida (1987).

Remarks. Gidley (1922) described 3 species of Sigmodon from Arizona: S. medius from the early Blancan Benson LF; S. minor, a smaller cotton rat, from the late Blancan Curtis Ranch LF; and S. curtisi, a large cotton rat, also from the Curtis Ranch LF. Sigmodon intermedius was described by Hibbard (1938) based on fossils from Rexroad Locality 2 and later Rexroad Locality 3. Hibbard characterized S. intermedius as intermediate in size between S. curtisi and S. medius. Cantwell (1969) synonymized S. intermedius and S. minor with S. medius. Statistical comparisons later led Martin (1970) also to consider S. intermedius to be synonymous with S. medius. Later, Martin (1979) designated the subspecies S. medius medius distinct from S. minor from Curtis Ranch. Still later, Martin (1986) synonymized S. medius and S. minor as populations S. minor /medius and S. minor /minor, which represent stages or chronomorphs on a chronocline that, at least in

Kansas, document a phyletic decrease in body size during late Blancan time that culminated in the diminutive S. minor/minor in the latest Blancan Borchers LF. S. minor /medius is a common member of early and middle Blancan faunas in Kansas, Texas, Arizona, and California, and Martin (1993) notes that cotton rats are the ecological analogues of their northern arvicolid cousins, members of the genus Microtus, and that they generally replace Microtus wherever the two are sympatric. It should be noted here that no arvicolids (microtines) were recovered from the Red Corral LF. The predominance of Sigmodon, a grazer, in the Red Corral LF indicates that some kind of mesic or semi-mesic lowland environment was present. For more detailed information on the evolution and dispersal of cotton rats, the reader is referred to Martin (1979, 1986, 1993), Martin et al. (2002b, 2003), and Peláez-Campomanes and Martin (2005).

Neotoma (Paraneotoma) cf. fossilis Gidley, 1922Figures 21A-D; 22-27

Referred specimens. Pit C: 4457, palate with left and right M1-

34

FIGURE 22. Graph showing range of variation in length (L) and width (W) in millimeters of M1s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: s = sawrockensis; f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D.

FIGURE 23. Graph showing range of variation in length (L) and width (W) in millimeters of m1s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D.

35

FIGURE 24. Graph showing range of variation in length (L) and width (W) in millimeters of M2s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; t = taylori; C = Proctor Pit C; D = Proctor Pit D.

FIGURE 25. Graph showing range of variation in length (L) and width (W) in millimeters of m2s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: s = sawrockensis; f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D.

M2’s

36

FIGURE 26. Graph showing range of variation in length (L) and width (W) in millimeters of M3s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; l = leucopetrica; t = taylori; C = Proctor Pit C; D = Proctor Pit D.

FIGURE 27. Graph showing range of variation in length (L) and width (W) in millimeters of m3s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D.

37

M2; 4458, left maxillary with M1-M2; 4459, left maxillary fragment; 4460, left maxillary fragment; 4461, isolated teeth. Pit D: 4045, associated left m1-m3 and right m1-m3 of one individual; 4046, left maxillary fragment with M1; 4047, isolated teeth.

Description. The wood rat from the two Red Corral pits is represented mainly by isolated teeth. No dentaries or dentary fragments were recovered, although a complete left and right lower dentition (Fig. 21C) was found in one washer box, and there is also a palate with both left and right M1s and M2s (Fig. 21A) and a left maxillary with M1 and M2 (Fig. 21B). The teeth exhibit characteristics of the subgenus Paraneotoma, including the S-shaped m3. They are moderately low-crowned and are smaller with thinner enamel than those of Neotoma quadriplicata from Rexroad Locality 3 with which they were compared.

In the lower molars, the apices of the labial folds (flexids) are nearly perpendicular to the long axis of the tooth, whereas the apices of the lingual folds (flexids) are directed anterolabially to the long axis. In the lower m1s (e. g. Fig. 21D), the anterolophid is confluent and the anterolingual fold is poorly developed or absent. In younger individuals, the fold is broad, shallow, and not deep so that it is generally lost with wear. The apex of the posterolabial fold is significantly anterior to the apex of the posterolingual fold, giving the mesolophid a constricted or staggered appearance with its labial end well anterior to its lingual end. The posterolophid is confluent.

The lower m2 is similar to the m1 in having three major lophids, but all are confluent. The mesolophid is diagonal to the long axis of the tooth with the labial apex more anterior than the lingual. With wear the anterior labial fold and the posterior lingual fold disappear, and the tooth acquires an S-shaped pattern. In the lower m3, the anterolabial fold and the posterior lingual fold are not developed, and the tooth has the S-shape characteristic of the subgenus Paraneotoma.

In the upper M1 and M2, the labial folds (flexi) extend posterolingually with the tips bent further posteriorly, whereas the lingual folds (flexi) are nearly perpendicular to the long axis of the tooth. In M1, the anteroloph is confluent. The anterolingual fold is slightly to poorly developed and is quickly lost with wear. The anterolabial fold and the mesolingual fold meet at the approximate midline of the tooth, thus separating the diagonally aligned anteroloph from the diagonally aligned mesoloph. M2 is similar to M1. The anteroloph is confluent, and the anterolingual fold is not present. As in M1, the anterolabial fold and the shallow mesolingual fold are arranged so that the diagonally aligned anteroloph is set off from the diagonally aligned mesoloph. The posteroloph is confluent and hook-like. M3 is similar to M2. All three lophs are confluent, and the anteroloph is set off from the mesoloph. The mesolingual fold is shallow, giving the tooth an E-shape. The posterolingual fold is absent in all three upper molars. A statistical summary of tooth measurements from both Pits C and D is given in Table 11.

Zakrzewski (1991, 1993) states that the folds are deeper and closer to the base of the crown in extant taxa than in extinct ones, and that this controls the occlusal pattern at different stages of wear. In the Red Corral teeth, the distances from the base of the crown to the base of the folds is less than that seen in other Blancan taxa such as Neotoma quadriplicata from Rexroad Locality 3 and Deer Park (Martin et al., 2002b) and N. leucopetrica from the White Rock LF (Zakrzewski, 1991). This discrepancy is probably the result of the smaller size and more brachydont nature of the Red Corral teeth so that in a relative sense the folds are not as deep. Crown depths of the Red Corral teeth are also given in Table 11. It should be noted that the bases of the folds on m2 in the Red Corral sample are at a greater distance from the base of the crown than in m1. Zakrzewski (1991) found this to be the case in N. leucopetrica as well.

The lower molars and the upper M3 from Pit D average 0. 1 shorter and narrower than those from Pit C, whereas the upper M1s and M2s from the two sites are nearly equal in size. Very likely the same species is represented at both localities. In general, the Red Corral teeth are smaller than those of Neotoma quadriplicata from Rexroad Locality 3, although there is some overlap in size. In particular, the m1s, m2s, and M1s average 0. 25-0. 4 shorter and 0. 05-0. 33 wider than those from Rexroad Locality 3, whereas the m3s are 0. 15-0. 25 shorter and 0. 15-0. 3 narrower. No measurements of the M2s and M3s from Rexroad Locality 3 were available for comparison. Of 15 m1s from Pit C and 13 (of 14) m1s from Pit D, the average lengths are 3. 15 (3. 0-3. 3) and 3. 06 (2. 8-3. 5), respectively, and the average widths are

1. 99 (1. 8-2. 2) and 1. 89 (1. 7-2. 1), respectively. The average length/width ratios are 1. 59 (1. 43-1. 78) for Pit C and 1. 63 (1. 48-1. 84) for Pit D. By comparison, the average length of 30 m1s from Rexroad Locality 3 is 3. 39 (2. 96-3. 80), and the average width is 1. 86 (1. 56-2. 13) according to Martin et al. (2002b). Of 18 M1s from Pit C and 19 M1s from Pit D, the average lengths are 3. 31 (3. 1-3. 5) and 3. 25 (3. 0-3. 5), respectively, and the average widths are 2. 28 (2. 15-2. 5) and 2. 25 (2. 1-2. 4), respectively. The average length/width ratios are 1. 45 (1. 36-1. 55) for Pit C and 1. 45 (1. 25-1. 59) for Pit D. By comparison, the average length of 10 M1s from Rexroad Locality 3 is 3. 58 (2. 96-3. 86), and the average width is 1. 96 (1. 68-2. 34) (Martin et al., 2002b). Other measurements of N. quadriplicata teeth from Rexroad Locality 3 as well as those from Deer Park B are given by Martin et al. (2002b).

According to Zakrzewski (1993), the number of anatomical roots in wood rats is a character that appears to be in a state of flux. All Blancan wood rats that he examined have two major roots on each of their lower molars, and three on their uppers. He noted that a small accessory root may be found, usually equidistant from the three major ones, on the M1 in Blancan taxa. The Red Corral teeth conform to this pattern. Nearly all of the upper M1s in which the roots are preserved possess a tiny nub in the position of the fourth rootlet. In four M1s from Pit C, a tiny rootlet measures 0. 2, 0. 3, 0. 3, and 0. 4 in length, and in three M1s from Pit D, a tiny rootlet measures 0. 3, 0. 3, and 0. 4 in length. In two M3s from each locality, the two anterior roots are fused.

Remarks. Hibbard (1967) erected the subgenus Paraneotoma to include three species: Neotoma (Paraneotoma) quadriplicatus, N. (P. ) sawrockensis, and N. (P. ) taylori. Tomida (1987) demonstrated that N. fossilis Gidley from the early Blancan Benson and Duncan (UA loc. 7937) local faunas of Arizona also shares the characteristics of Paraneotoma, and he referred it to that subgenus. Czaplewski (1990) named Neotoma vaughani from the early Blancan Verde LF of Arizona and referred it to the same subgenus. Zakrzewski (1991) named N. leucopetrica from the late Blancan White Rock LF of Kansas (Eshelman, 1975) and assigned it to the same subgenus. These six species share similar but somewhat variable tooth morphologies and are distinguished to some extent by molar size, crown height, and depth of the reentrant folds (flexi and flexids). The Red Corral wood rat teeth are larger than those of N. sawrockensis from the earliest Blancan Saw Rock Canyon LF of Kansas (Hibbard, 1967) and are slightly larger or overlap in size those of N. fossilis from Arizona (Gidley, 1922; Tomida, 1987). They approximate in size the few described teeth of N. vaughani. As noted above, the Red Corral teeth are smaller and have thinner enamel than those of N. quadriplicata from Rexroad Locality 3, and they are also smaller than teeth from the Deer Park LF referred to N. quadriplicata by Martin et al. (2002b). The Red Corral teeth are smaller than those of N. taylori with which they were compared from the Borchers LF of Kansas (Hibbard, 1967). They are also smaller than teeth referred to N. taylori from UA locality 15-24, 111 Ranch LF of Arizona, but overlap in size teeth referred to that species from UA loc. 7933, 111 Ranch (Tomida, 1987). N. taylori is the most hypsodont species within the subgenus Paraneotoma. As a result, the side walls of the cheek teeth are straighter (or less curved) than in other species of the subgenus, and, thus, the cheek teeth of N. taylori are less rounded or less inflated in appearance, especially in the lower molars (Tomida, 1987). The largest species in this subgenus is N. leucopetrica, and the smallest is N. sawrockensis. Dalquest (1978) assigned several teeth from the Beck Ranch LF to N. cf. sawrockensis, but Tomida (1987) noted that these teeth appear to be slightly larger and higher crowned than that species and more equivalent in size to the teeth from the Duncan LF that he assigned to N. fossilis. C. A. Repenning tentatively identified the Beck Ranch fossils as N. fossilis (pers. comm. to Tomida, Jan. 1981). A comparison of the length and width of the molars of several species of Neotoma from Blancan faunas in Kansas and Arizona is given in Figures 22-27.

Zakrzewski (2006) noted the variation in tooth dimensions of woodrat samples from the Meade Basin in southwestern Kansas including published sites such as Saw Rock Canyon, Rexroad Locality 3, and Borchers as well as from several unpublished sites (e. g. XIT 1B and Wendell Fox). He concluded that the data “suggest the presence of two additional woodrats in the basin, a small taxon at XIT 1B that may be in a lineage with Neotoma sawrockensis and a larger taxon at Wendell Fox that may be in a lineage with N. leucopetrica. ” He did not name these taxa and, until the geographic and biostratigraphic variation within and between populations of Blancan woodrats in the central and

38

southwestern United States is better known, it seems prudent not to designate a new species for the Red Corral wood rat.

Order CarnivoraFamily Canidae

Canis lepophagus Johnston, 1938Figures 28A-B

Referred specimens. Pit B: F:AM 62987, mandible with right dentary possessing alveoli of p2-m2 and anterior portion of left dentary possessing canine, p2, and alveoli of p3 and p4. Pit C: 4241, left dentary fragment with alveolus of p3, broken p4, complete m1-m2, and alveolus of m3; 4242, associated right and left dentaries; unnumbered incisors and upper P4 carnassials. Pit D: 4107, left maxillary fragment with P2 and alveoli of P1 and P3; 4108; left maxillary fragment with P3-M2; 4208, isolated teeth; 4109, left calcaneum.

Description. The left dentary, 4241 (Fig. 28B), is the size of that of Holocene Canis latrans Say. The crown of p4 is missing. Measurements of m1 are: AP L = 22. 4; labial length of trigonid to notch = 15. 8; maximum width across trigonid = 8. 6; width of talonid = 8. 2. AP L of m2 = 10. 8; TW of m2 = 8. 0. Length of m1-m3 alveolus = 38.

0. Lingual jaw depth below m1 talonid = 20. 0. The associated left and right dentaries, 4242 (Fig. 28A), are

smaller than 4241 and are shorter, narrower, and less deep than those of the paratype of Canis lepophagus from the Cita Canyon LF of Texas and of the modern coyote but are larger than the dentaries of the modern red fox, Vulpes vulpes. All of the cheek teeth are present except for the posterior half of the left m2 and the peg-like left m3. The jaws are broken anterior to the canines, but a few incisors were found in association. Measurements below were taken on the more complete right mandible and closely match those given by Kurtén (1974, p. 31) for the same specimen. L p2 = 9. 0; W p2 = 3. 6; L p3 = 10. 4; W p3 = 3. 9; L p4 = 11. 9; W p4 = 5. 0; L m1 = 19. 2; W m1 = 7. 1; L m2 = 8. 8; W m2 = 6. 4; L of p2-p4 = 33. 5; L of m1-m3 = 31. 3; lingual jaw depth below m1 = 18. 7.

Tedford et al. (2009, p. 113) mentioned the mandible, 62987, from Pit B but did not provide measurements. The right dentary is more complete and retains the condylar and angular processes, but the tip of the coronoid process is missing, as are all of the teeth. The alveolar length of p2-m3 is 72. 5. The labial jaw depth below the m1 alveolus is 21. 2. The left dentary retains p2 and the canine but is broken posterior

TABLE 11. Statistical summary of tooth measurements (in mm) of Neotoma (Paraneotoma) cf. fossilis from Red Corral Pits C and D. Measurements and abbreviations after Zakrzewski (1991): L = greatest occlusal length; W = greatest occlusal width; L/W = length/width ratio; ab = height of anterobuccal (labial) fold above base of crown; pb = height of posterobuccal (labial) fold above base of crown; al = height of anterolingual fold above base of crown; ml = height of mesolingual fold above base of crown; pl = height of posterolingual fold above base of crown.

Red Corral Pit C Measure N OR Mean SD Measure N OR Mean SD

m1 L 15 3. 0-3. 3 3. 15 0. 112 M1 L 18 3. 1-3. 5 3. 31 0. 128W 15 1. 8-2. 2 1. 99 0. 118 W 18 2. 15-2. 5 2. 28 0. 09

L/W 15 1. 43-1. 78 1. 59 0. 102 L/W 18 1. 36-1. 55 1. 45 0. 05ab 14 0. 2-0. 8 0. 43 0. 161 ab 18 0. 2-0. 6 0. 41 0. 102pb 14 0. 2-0. 8 0. 47 0. 168 pb 18 0. 2-0. 5 0. 37 0. 083al 2 1. 5-1. 7 1. 6 al 9 0. 4-1. 1 0. 88 0. 217ml 14 0. 3-0. 8 0. 59 0. 144 ml 16 0. 3-0. 7 0. 52 0. 169pl 13 0. 4-1. 0 0. 71 0. 173

m2 L 14 2. 6-2. 9 2. 77 0. 114 M2 L 16 2. 4-2. 7 2. 52 0. 106W 14 2. 0-2. 3 2. 15 0. 076 W 16 1. 8-2. 2 2. 02 0. 091

L/W 14 1. 23-1. 40 1. 29 0. 048 L/W 16 1. 14-1. 39 1. 25 0. 076ab 12 0. 5-1. 2 0. 85 0. 225 ab 15 0. 2-0. 5 0. 34 0. 074pb 14 0. 3-0. 8 0. 58 0. 163 pb 15 0. 1-0. 4 0. 3 0. 086ml 14 0. 5-0. 9 0. 68 0. 112 ml 16 0. 2-0. 6 0. 42 0. 098pl 13 0. 5-1. 2 1. 02 0. 213

m3 L 11 2. 0-2. 4 2. 24 0. 121 M3 L 8 1. 9-2. 3 2. 06 0. 124W 11 1. 6-1. 9 1. 75 0. 093 W 8 1. 6-1. 8 1. 75 0. 076

L/W 11 1. 22-1. 35 1. 28 0. 041 L/W 8 1. 06-1. 28 1. 18 0. 07ab 7 0. 3-1. 0 0. 49 0. 248

pb 11 0. 3-0. 8 0. 48 0. 16 pb 7 0. 1-0. 4 0. 25 0. 096ml 11 0. 2-1. 1 0. 48 0. 26 ml 7 0. 2-0. 4 0. 3 0. 058

Red Corral Pit DMeasure N OR Mean SD Measure N OR Mean SD

m1 L 13 2. 8-3. 5 3. 06 0. 18 M1 L 19 3. 0-3. 5 3. 25 0. 15W 14 1. 7-2. 1 1. 89 0. 122 W 19 2. 1-2. 4 2. 25 0. 102

L/W 13 1. 48-1. 84 1. 63 0. 092 L/W 19 1. 25-1. 59 1. 45 0. 078ab 13 0. 1-0. 7 0. 4 0. 188 ab 17 0. 1-0. 5 0. 32 0. 11pb 13 0. 2-0. 75 0. 52 0. 187 pb 16 0. 1-0. 5 0. 29 0. 09

al 11 0. 2-1. 2 0. 75 0. 281ml 13 0. 2-0. 7 0. 48 0. 168 ml 18 0. 2-0. 6 0. 44 0. 128pl 13 0. 3-0. 9 0. 66 0. 187

m2 L 12 2. 5-2. 9 2. 67 0. 123 M2 L 14 2. 3-2. 8 2. 56 0. 128W 13 2. 0-2. 1 2. 02 0. 038 W 14 1. 8-2. 1 2. 01 0. 073

L/W 12 1. 25-1. 45 1. 32 0. 058 L/W 14 1. 19-1. 40 1. 28 0. 055ab 8 0. 5-1. 0 0. 6 0. 177 ab 8 0. 2-0. 5 0. 36 0. 098pb 11 0. 2-0. 8 0. 49 0. 17 pb 9 0. 2-0. 6 0. 32 0. 13ml 11 0. 2-0. 7 0. 49 0. 168 ml 11 0. 2-0. 5 0. 35 0. 104pl 10 0. 7-1. 2 1 0. 156

m3 L 7 1. 9-2. 3 2. 13 0. 125 M3 L 8 1. 7-2. 0 1. 89 0. 136W 7 1. 5-1. 8 1. 62 0. 122 W 8 1. 5-1. 8 1. 63 0. 128

L/W 7 1. 12-1. 47 1. 32 0. 127 L/W 8 1. 06-1. 25 1. 16 0. 068ab 3 0. 1-0. 4 0. 3 0. 141

pb 7 0. 3-0. 5 0. 39 0. 084 pb 3 0. 0-0. 3 0. 1 0. 173ml 6 0. 2-0. 5 0. 35 0. 122 ml 4 0. 15-0. 50 0. 26 0. 16

39

FIGURE 28. Canis lepophagus: A, left dentary, c, p1-m2, 4242, Pit C; B, left dentary, p4-m2, 4241, Pit C. Urocyon sp. : C, right m1, 4110, Pit D. Borophagus diversidens: D, canine, 4103, Pit D; E, left maxillary, M1, 4243, Pit C; F, right calcaneum, 4248, Pit C; G, left metacarpal IV, 4106, Pit D. Trigonictis cookii: H, left P4, 4112, Pit D; I, right femur, 4116, Pit D. Bassariscus sp. : J, right M2, 4198, Pit D.

40to the m1 alveolus. The jaws appear to compare in size with most other jaws assigned to this species.

In the left maxillary fragment, 4107, L P2 = 12. 2 and W P2 = 5. 0. In the left maxillary fragment, 4108, P3 and P4 are broken and cannot be accurately measured. L M1 = 14. 0; W M1 = 17. 8; L M2 = 7. 5; W M2 = 12. 0.

Remarks. Hibbard (1941c) referred a small canid dentary, KU 4602, from Rexroad Locality 3 in Kansas to Canis lepophagus. His measurements indicate an individual about the size of 4242. Kurtén (1974, p. 31) gave measurements of 4241 and 4242 from Red Corral and stated (p. 5) that “The two specimens differ markedly in size but since both are within the variation range of C. lepophagus, and the large specimen is much smaller than wolf-like forms such as C. texanus, both are here regarded as coyote. ”It should be noted that C. texanus was later transferred to the South American genus Protocyon by Kraglievich (1952) and later to Xenocyon by Tedford et al. (2009). Nowak (1979) reviewed the species of Canis and concluded that all Blancan specimens despite their variable size are referable to C. lepophagus. Tedford et al. (2009, p. 109) referred 3 teeth (UMMP 37132) from the early Blancan Rexroad Locality 3 LF of Kansas to a slightly smaller species, C. ferox, but did not discuss Hibbard’s specimen, KU 4602. C. ferox was originally described by Miller and Carranza-Castañeda (1998) based on a skull, mandible, and other material from a late Hemphillian locality in Guanajuato, Mexico. Tedford et al. (2009) referred additional late Hemphillian as well as early Blancan specimens from Mexico and the United states to C. ferox. It is possible that KU 4602 may also be that of C. ferox but more than likely Hibbard (1941c) was correct in assigning it to C. lepophagus. It also seems unlikely that there would be two species of coyote in the Red Corral LF and, therefore, I follow Kurtén (1974) and Novak (1979) in recognizing a wide range of variation in C. lepophagus and assign both 4241 and 4242 to that species.

Urocyon sp. Figure 28C

Referred specimens. Pit D: 4110, right m1; 4111, left M1. Description. A gray fox is represented in the fauna by two teeth

that are inadequate for species identification. The right m1, 4110 (Fig. 28C), measures 12. 8 long, 5. 1 wide across the trigonid and 4. 8 wide across the talonid. The protoconid is high. The metaconid is slightly higher than the paraconid as in modern Urocyon cinereoargenteus, but it is a prominent cone-shaped cusp distinctly separated from the paraconid. A small protostylid is appressed to the posterolateral surface of the protoconid. This feature is frequently present in modern Urocyon but was absent in all Vulpes jaws examined. A low, narrow mesoconid ridge connects the protoconid and hypoconid. A well-developed hypoconulid is situated posterior to the hypoconid. The lingual edge of the talonid basin contains three small entoconulids. A narrow, medially notched transverse cristid connects the hypoconid and the entoconid.

The left M1, 4111, is slightly weathered and much of the enamel is gone. The tooth dimensions are near the mean for Urocyon cinereoargenteus as given by Stevens (1965). The anteroposterior diameter is 8. 2 as measured along the external border, and the transverse diameter is 9. 9. The protocone, paraconule, hypocone, and metaconule are worn; the paracone is higher than the metacone, and the distance between the apices of these cusps is 4. 8. The external cingulum appears to be weak or absent, but this may be partially due to loss of enamel through weathering. The anterior cingulum joins the paraconule ridge between the paraconule and the paracone. The posterior cingulum extends well laterally and joins the metaconule ridge between the metaconule and the metacone.

Remarks. Remains of the gray fox are quite rare and usually fragmentary in Blancan faunas of the Great Plains and western states. They are frequently assigned simply to Urocyon sp., as in the case of a left P4, a right P4, a left p2, and a left m2 from the early Blancan Beck Ranch LF from Scurry County, Texas (Dalquest, 1978, p. 287), a possible record from the Broadwater LF of Nebraska, and undescribed material from the Arroyo Seco (Blancan) and Vallecito Creek (Irvingtonian) faunas of the Anza-Borrego region of California (Cassiliano, 1999).

Stevens (1965) described Urocyon progressus from Rexroad Locality 3 (early Blancan), Meade County, Kansas. The holotype is a left parietal. An incomplete left tibia and a left M1 were designated as paratypes. Bjork (1974, p. 25) referred an edentulous fragmentary right maxillary and jugal from the type locality to this species and Tedford et al. (2009, p. 71) tentatively referred a right partial maxilla with P1 alveolus and P2-P4 which they figured (p. 70, figs. F-G) and a cranial

fragment from the same locality. Akersten (1972, p. 19) referred to this species an edentulous dentary fragment from the Red Light LF (late Blancan), Hudspeth County, Texas.

Tedford et al. (2009, p. 72-73) described Urocyon galushai from the 111 Ranch (Dry Mountain) locality (late Blancan), San Simon Valley, Graham County, Arizona, and referred to this species the specimens mentioned above from Beck Ranch, Red Light, and Vallecito Creek as well as additional material from the Palm Springs Formation, San Diego County, California, and two hitherto unpublished teeth (a right M1 and a lower left canine) from the late Blancan Cita Canyon LF, Randall County, Texas. They also described U. citrinus from the Inglis site 1A (early Irvingtonian), Citrus County, Florida (Tedford et al., 2009, p. 73-75). In addition, they stated (p. 72) that because of the fragmentary nature and questionable association of the material assigned to U. progressus, the species cannot be properly diagnosed at the present time. They further stated (p. 73) that the M2 used by Getz (1960, p. 363) to describe U. atwaterensis from the Borchers LF (late Blancan), Meade County, Kansas, is not diagnostic, as this tooth shows great variability in modern U. cinereoargenteus, and, therefore, the fossil species is a nomen vanum.

The Red Corral teeth cannot be adequately compared with Urocyon progressus as the m1 of that species is unknown and the weathering of the Red Corral M1 has obliterated some of the diagnostic features. The paratype left M1 of U. progressus is an unworn tooth and is larger than the Red Corral tooth. Adequate comparison with the m1 and M1 in the type of U. galushai is rendered difficult, as these teeth are broken. I have not examined the m1 of U. citrinus but the tooth appears to have a wider talonid than that of the Red Corral m1. Tedford et al. (2009, p. 210, appendix 3, table 5) give the measurements as L = 12. 0; W of trigonid = 4. 0; W of talonid = 5. 0.

Borophagus diversidens Cope, 1892Figures 28D-G

Referred specimens. Pit C: 4243, left maxillary fragment with M1; 4244, right M1; 4245, left M1; 4246, left upper canine; 4247, isolated teeth including an incisor and two m3s; 4231, distal right humerus; 4248, right calcaneum; 4249, partial metapodials. Pit D: 4102, incisors; 4103, canine; 4104, canine; 4105, isolated molars and premolars; 4106, left metacarpal IV. Wang et al. (1999, pp. 303-304) referred to this species several specimens collected from the fauna by parties from the Frick Laboratories and currently housed in the American Museum of Natural History. From near Pit A: F:AM 67334, right partial ramus with p3-m2 all broken at bases. From Pit C: F:AM 67333, right partial ramus with c1 and p3 alveoli, p4-m1 and m2 alveolus, and right isolated m1; and F:AM 129871, left isolated worn m1. From Pit D: F:AM 67364, left ramus with c1 alveolus, p2 alveolus-m2, m3 alveolus (Wang et al., 1999, figs. 128A-B) and associated detached right canine; F:AM 67365, crushed fragmentary skull with P4-M1 and isolated teeth including M2 and premolars; and F:AM 129870, left partial maxillary with P4 broken-M1.

Description. Fossil specimens recovered from the fauna by the author are quite fragmentary. Most of the teeth are broken or worn and do not yield useful measurements. The most complete specimen is a left maxillary fragment, 4243 (Fig. 28E), containing the posterior root of P4 and a nearly complete but worn M1. The right M1, 4244, appears to represent the same individual. The canine, 4103 (Fig. 28G), is very robust. Crown height is 26. 5, and the greatest diameter is 16. 9.

Wang (written communication, 2015) graciously provided the following measurements of the F:AM specimens: Pit C, 67333, L p4 = 21. 0, W p4 = 16. 3, L m1 = 33. 5, W m1 trigonid = 14. 7, W m1 talonid = 13. 1; Pit D, 67364, L p3 = 10. 4, L p4 = 21. 5, W p4 = 14. 8, L m1 = 32. 5, W m1trigonid = 15. 1; W m1 talonid = 13. 0, L m2 = 12. 8, Wm2 = 9. 0; Pit D, 67365, L P4 = 30. 0, L M1 = 17. 5.

The distal portion of a right humerus, 4231, has had some restoration. The greatest width across the capitulum and medial condyle is approximately 63. The least anteroposterior diameter of the articulating ulnar surface is 15. 7. Measurements of the right calcaneum, 4248 (Fig. 28F), are: greatest L = 54. 8; width across medial articular facet perpendicular to long axis = 25. 5; greatest posterior W of calcaneal tuber = 19. 2. The left metacarpal IV, 4106 (Fig. 28G), is complete and well-preserved. The proximal articular surface is convexly arched and articulates with the distal face of the unciform. The proximal end contains lateral facets for articulation with metacarpals III and V. The shaft is straight and nearly cylindrical in cross-section. The distal articular surface is smooth and convex cranially and sharply keeled caudally. Measurements are: L = 78. 9; proximal AP L = 15. 5;

41

proximal W = 12. 7; mid-shaft W = 9. 6; distal condyle L = 14. 0; distal condyle W = 12. 9.

Remarks. Borophagus diversidens is a common species in Blancan faunas in the Great Plains and the southwest United States.

Family MustelidaeTrigonictis cookii (Gazin, 1934b)

Figures 28H-IReferred specimens. Pit D: 4112, left P4 in bone fragment;

4113, right m1; 4114, right upper canine and left lower canine; 4115, edentulous left dentary; 4116, right femur; 4209, left femur; 4210, right metacarpal I. Bivins Pit 2: F:AM 62740, left dentary with c, p2, p3, p4 alveolus, m1, and m2 alveolus.

Description. The left P4, 4112 (Fig. 28H) shows the typical characteristics of Trigonictis upper carnassials. The tooth is elongate and triangular in occlusal view and is strongly indented along the anterior border. A cingulum extends across the anterior border of the tooth and continues posteriorly in a straight line from the protocone to the posterolingual base of the metacone. The protocone rises from the cingulum as a small but distinct cusp. An incipient hypocone is present on the lingual cingulum opposite the paracone. The talon enclosed by the cingulum, protocone, hypocone, and paracone is basined. The parastyle is merely a slight upward projection of the anterior cingulum. A good shearing blade is formed by the ridge connecting the paracone and metacone. Measurements of P4 for T. cookii and other species of Trigonictis are given in Table 12.

Note: The Hagerman specimens originally described as T. idahoensis and the Rexroad specimens originally described as T. kansasensis were synonymized with T. macrodon by Ray et al. (1981).

The right m1, 4113, is long and slender with a well-developed and deeply notched carnassial blade. The trigonid is longer than the talonid, and the metaconid is strongly developed and separated from the base of the protoconid by a shallow notch. The talonid is broad and basined with a prominent but worn hypoconid that is separated from the protoconid by a broad deep notch. The posterior border of the talonid slopes lingually. Measurements of m1 for Trigonictis cookii and other species of Trigonictis are given in Table 13. Note that the Red Corral specimen is slightly larger than m1s of T. cookii from Idaho.

Two canines, 4114, are referred to this species. The upper canine, 4114a, compares in size with that in a partial skeleton of Trigonictis cookii, UMMP V 49819, from Hagerman, Idaho. The lower canine, 4114b, is more slender and less robust than that of V 49819.

An edentulous left dentary fragment, 4115, broken across the alveoli of p2 and m2, is tentatively referred to Trigonictis cookii. The jaw is larger, longer and deeper than those of T. cookii from Hagerman, however. The alveolar length of p3-m1 is comparable to that in most T. “idahoensis” and the holotype of T. “kansasensis,” but the anterior premolars were more crowded. The alveoli of the posterior root of p3 and the anterior root of p4 are confluent as are the posterior root of p4 and the anterior root of m1. The alveolus of the posterior root of p2 is posterolabial to that of the anterior root of p3. The jaw is not as deep as that of T. “idahoensis” or T. “kansasensis. ”Lingual jaw depth below m1 is 12. 0.

The right femur, 4116 (Fig. 28I), is complete and compares in size with the right femur, V 49819, of Trigonictis cookii from Idaho. The trochanteric fossa is deeply excavated, and the greater trochanter extends down the lateral surface of the shaft to the level of the lesser trochanter. The left femur, 4209, is similar but slightly shorter and is missing part of the distal condyle. Comparative measurements of the three femora are given in Table 14. Measurements of the metacarpal, 4210, are L = 30. 2, proximal W = 7. 3, and distal W = 5. 7.

The left dentary, F:AM 62740, is not part of the Red Corral LF but comes from the Bivins Pit 2 LF located in northern Oldham County about 11. 2 km (7 miles) south of Channing and about 14. 4 km (9 miles) east of Proctor Pit D. It is described here for comparison purposes because it comes from sedimentary deposits exposed along Middle Cheyenne Creek that are of similar age, lithology and reddish brown color as those at Proctor Pit D. The jaw is dark reddish brown as are the fossils from Pit D. It is nearly complete, lacking only p4, m2 and the angular process. The length of c-m1 is 37. 0 and that of p2-m1 is

TABLE 12. Measurements (in mm) of P4 in Trigonictis species. Abbreviations: APL = anteroposterior length; Pr. W = protocone width; Pa. W. = paracone width * = measurements by Hibbard (1941b, 1941c); ** = measurements from Bjork (1970); *** = measurements by Ray et al (1981); other measurements by the author.

Name Museum No. Faunal Loc. Side APL Pr. W. Pa. W. T. cookii WTAMU-V-4112 Red Corral D, TX Left 9. 6 5. 9 4. 7T. cookii** UMMP V-49819 Hagerman, ID Right 9. 6 5. 7 4. 5T. "idahoensis" USNM 23664 Hagerman, ID Left 11. 3 7. 1 5. 4T. "idahoensis" UMMP V-49728 Hagerman, ID Left 11. 6 7 5. 4T. "kansasensis" type*

KU 4604 Rexroad Loc. 3, KS Left 11. 9 7. 8 6. 6

T. "kansasensis" UMMP V-51874 Rexroad Loc. 3, KS Right 10. 9 7. 1 5. 6T. macrodon type*** ANSP 11626 Maryland Left 11. 6 7. 6TABLE 13. Measurements (in mm) of m1 in Trigonictis species. Abbreviations: APL = anteroposterior length; Tg. L. = trigonid length; Tg. W. = trigonid width; Tl. W. = talonid width. * = measurements by Gazin (1934b); ** = measurements by Bjork (1970); *** = measurements by Hibbard (1941b, 1941 c); **** = measurements by Ray et al (1981); other measurenens by the author. NA = not available.

Name Museum No. Faunal Loc. Side APL Tg. L. Tg. W. Tl. W. T. cookii WTAMU-V-4113 Red Corral D,

TX Right 12. 1 8. 2 5. 2 5. 1

T. cookii F:AM 62740 Bivins Pit 2, TX Left 12. 2 8. 1 5. 1 4. 9

T. cookii type* USNM 12606 Hagerman, ID Right 10. 7 7. 2 4. 6 4. 5T. cookii UMMP V-49819 Hagerman, ID Right 11. 6 7. 7 4. 8 4. 8T. cookii UMMP V- 55514 Hagerman, ID Left 11. 6 7. 8 5. 1 4. 8T. cookii** USNM 12608 Hagerman, ID Left 11. 7 NA 4. 9 NAT. cookii** USNM 25138 Hagerman, ID Left 11. 5 NA 5. 1 NAT. macrodon type**** ANSP 11626 Maryland Right 12. 2 >9. 0 5. 7 NAT. "idahoensis" type* USNM 12030 Hagerman, ID Left 14. 2 9. 9 6. 3 6T. "kansasensis" type*** KU 4604 Rexroad Loc.

3, KS Right 14. 8 10 6. 4 6

TABLE 14. Measurements (in mm) of femurs in Trigonictis cookii from Hagerman LF, Idaho (Bjork,1970) and Red Corral Pit D. NA = measurement not available. Measurement V49819

Hagerman, IDWTAMU -

V-4116WTAMU - V-4209

Length 67 71. 9 69Proximal width 16. 9 18. 2 16. 9Proximal depth NA NA NAMidshaft width 6. 3 6 5. 5Midshaft depth 5. 4 5. 7 5. 2 Distal width NA 15. 9 NA Distal depth NA 13. 6 NA

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FIGURE 29. Homotherium sp. : A, left dentary with 2 incisors, c, p4-m1, F:AM 144637, Pit B. Miracinonyx studeri: B, left dentary, c, p3-m1, F:AM 69255, Pit D. Taxidea sp. : C, left dentary, worn m1-m2, F:AM 62741, Pit B. Capromeryx sp. : D, left dentary, p2-m1, F:AM 117078, Pit D. Scale bar = 2 cm. for all specimens. 28. 0. The m1 is moderately worn; measurements as determined by the author are: L = 12. 2, maximum W = 5. 1, trigonid L = 8. 1, talonid W = 4. 9. The lingual jaw depth below m1 is 13. 0 and the jaw thickness is 6. 9. These measurements agree with those of Ray et al. (1981) except for their m1 length (12. 3) and trigonid length (8. 4).

Remarks. Two species of Trigonictis are known from Blancan

faunas in North America. Of these, the larger and better known is T. macrodon (Cope), which now includes in synonymy the formerly recognized species T. idahoensis (Gazin) and T. kansasensis Hibbard (see Ray et al., 1981). The smaller species, T. cookii (Gazin), is about two-thirds the size of T. macrodon and is known from the Hagerman (Gazin, 1934b, 1937; Zakrzewski, 1967; Bjork, 1970) and Grandview

43(Shotwell, 1970) local faunas of Idaho; the Sand Draw (Skinner et al., 1972, p. 109, F:AM 49160) and Broadwater (Anderson, 1984) local faunas of Nebraska; the 111 Ranch LF of Arizona (Galusha et al., 1984), and the Red Corral LF of Texas (Anderson, 1984). Its occurrence in the Red Corral and Bivins Pit 2 local faunas is the first record of this species from the southern Great Plains. Zakrzewski (1967) showed that, although there is some overlap in size between the two species, T. cookii is a distinct species rather than a female of T. idahoensis (= T. macrodon).

The lengths of the Red Corral m1 (12. 1) and the Bivins Pit 2 m1 (12. 2) are slightly greater than those of the Idaho specimens of Trigonictis cookii and, in fact, fall within the gap (11. 7-12. 6) used by Bjork (1970) to separate the Hagerman specimens of T. cookii and T. idahoensis first described by Gazin (1934b). However, the m1 length in the holotype of T. macrodon (ANSP 11626) from Maryland is 12. 2 and the minimum m1 length for any specimen assigned by Ray et al. (1981) to T. macrodon is 12. 0. Jaws containing similar-sized carnassials were reported from the White Bluffs LF, Washington (Gustafson, 1978) and the Sand Draw LF, Nebraska (Skinner et al., 1972, p. 109, F:AM 49163) as T. cookii. Using other variates, however, Ray et al. (1981) reassigned these specimens to T. macrodon. They also assigned the Bivins Pit 2 specimen to T. macrodon. However, the very diagnostic P4 and the femora from Red Corral compare easily in size with those of T. cookii (UMMP V49819) from Idaho and are considerably smaller than those of T. macrodon. The length of m1 and the small edentulous dentary from Red Corral closely match those measurements of the Bivins Pit 2 specimen. I, therefore, assign both the Red Corral and Bivins Pit 2 specimens to T. cookii pending the discovery of more specimens that might better delineate the range of variation within and the size differences between the two species.

Taxidea sp. Fig. 29C

Referred specimen. Pit B: F:AM 62741, a left dentary with the root of p3, the alveolus of p4, and very worn m1-m2.

Description. The dentary (Fig. 29C) is that of an old individual. It is broken anterior to p3 and beneath the entire tooth row. The first and second molars are worn very flat. Length and width of m1 are 14. 4 and 7. 6, respectively. The ascending ramus and articular condyle are well preserved, although a portion of the tip of the coronoid process has been restored, making the process appear more rounded than the more pointed process seen in recent Taxidea. The maximum height of

the ascending ramus from the top of the coronoid process to the ventral border of the jaw is 42. 0. The width of the articular condyle is 18. 7.

Remarks. The Pit B dentary is similar in size to that of the modern badger, Taxidea taxus. Remains of Taxidea are known from many Blancan local faunas including Rexroad Loc. 3 and Deer Park (Kansas); Broadwater and Sand Draw (Nebraska); Hagerman (Idaho);White Bluffs(Washington); Red Light, Beck Ranch, and Cita Canyon (Texas); Buckhorn (Morgan et al., 1997) and Tonuco Mountain (Morgan et al.,1998) of New Mexico; as well as Anita, Bear Springs, Country Club, and San Simon of Arizona (Morgan and White, 2005), but the genus is typically represented by only one or two specimens at a given locality. In the case of the Red Corral specimen, loss of the anterior and ventral portion of the dentary due to breakage plus the heavily worn condition of the molars prevent adequate comparison with the dentary of the modern badger.

Family ProcyonidaeBassariscus sp.

Figure 28JReferred specimen. Pit D: 4198, right M2. Description. The tooth (Fig. 28J) is small and triangular in shape

with well-developed protocone, paracone, and metacone – the paracone being slightly better-developed than the metacone. A small protoconule is present on the ridge connecting the protocone with the paracone. The hypocone and posterolingual cingulum are lacking. The size and cusp arrangement is similar to that observed in M2 of a modern skull of Bassariscus astutus, the ring-tail, examined by the author, except that the latter possesses a small hypocone and posterolingual cingulum making the tooth a bit wider than the fossil. According to Baskin (written communication, 2014), there is variation in the presence/absence of a hypocone in specimens that he has seen. The fossil tooth is 3-rooted. Measurements of the fossil are: anteroposterior length across paracone-metacone = 3. 1; transverse width across protocone-paracone = 4. 4 and across protocone-metacone = 4. 2.

Remarks. Czaplewski (1990, p. 34) described and figured a left M2 of Bassariscus sp. from the early Blancan Verde LF of Arizona. He gave the anteroposterior length as 3. 19 and the transverse width as 4. 41. He stated that “as in modern species of Bassariscus, the Verde M2 has all cingula greatly reduced. The paracone and metacone are sub equal in size, with the paracone being slightly larger. No parastyle is present. A faint protoconule and faint metaconule are present, but are much reduced and discernable only as slight swellings on the preprotocrista and postprotocrista, respectively. The internal cingulum is restricted to the posterolingual corner of the tooth and lacks a hypocone. ”

Fossil Bassariscus species are described mainly on the basis of lower teeth and jaws. Few upper dentitions are known and the Verde and Red Corral M2s are, apparently, the first fossil M2s to be described. The only known Blancan species of the genus is Bassariscus casei from the Rexroad 3 LF (Hibbard, 1952b). It is represented by a right dentary and a left maxillary fragment containing the posterior part of P3, P4, M1, and the alveolus of M2, so that a comparison with the Red Corral tooth is not possible. Hibbard stated that the fossil species is distinguished from the Holocene species by its narrower lower

TABLE 15. Measurements (in mm) of mandibles and lower dentitions of Miracinonyx studeri from Cita Canyon LF, Texas (WT 1218); Red Corral Pit C (WT 4223); Red Corral Pit D (F:AM 69255); and Guanajuato, Mexico (IGM 6676). Measurement WT

1218WT 4223

F:AM 69255 IGM 6676

Length, ant. of symphysis to post. of condyle 172. 9

Depth of jaw below anterior of p4 30 32 39. 5 ~22

Depth of jaw below posterior of m1 28. 2 31. 2 38. 2

Thickness of jaw at posterior of m1 15. 4 15. 5 15. 7 15. 0 at p4c-m1 inclusive 82. 6 94. 5 78. 3p3-m1 inclusive 55 57. 2 60. 5 47. 9c length at enamel base 13. 2 19. 4c width at enamel base 11. 1 13. 5c-p3 diastema 12. 5 15. 2 15. 4p3 length 15. 2 14. 2 16. 5 13. 4p3 width 8. 6 9. 4 10. 5 7. 1p4 length 18. 8 19. 9 19. 5 17. 6p4 width 9. 4 10. 3 10. 7 7. 5m1 length 22. 6 21. 8 23. 5 19. 6m1 width 10. 7 10. 9 11 7. 9Length of anterior blade of m1 10 10. 9 10Length of posterior blade of m1 13. 3 11 12. 2

TABLE 16. Measurements (in mm) of femora of Miracinonyx studeri from Red Corral Pit C (RC 4235) and modern Panthera leo (M-874) from Univ. Texas collection. Measurements are those used by Merriam and Stock (1932, p. 137-138). NA = not available.

Measurement (Merriam and Stock, 1932) RC 4235 right

RC 4235 left

Lion M-874

Greatest length 343 342 320Transverse diameter of proximal end NA NA 78Greatest anteroposterior diameter of head 33. 2 33. 2 35. 2Transverse diameter of shaft at middle NA 26 26. 1Anteroposterior diameter of shaft at middle 28. 9 31. 5 23. 3Greatest width across the distal extremity 64. 2 NA 62. 7Greatest anteroposterior dia. of distal extremity 66. 5 NA 67Greatest width of rotular surface 32. 4 32. 4 33Greatest width of intercondylar notch 18. 5 NA 17. 8Greatest width of articular surface of inner condyle 25. 2 NA 23. 7

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FIGURE 30. Miracinonyx studeri: A, left P3, 4225; B, right maxillary, P3-P4, 4224; C, right dentary, p3-m1, 4223. All specimens are from Pit C.

premolars and molars; by the more open valleys between the cusps; and by the well-developed internal cingulum of P4. B. casei is also reported, but not described,from the early Blancan Beck Ranch LF from Texas on the basis of two dentaries and isolated upper and lower teeth (Dalquest, 1978). The author has not had an opportunity to examine this material. The Red Corral specimen is not identifiable to species.

Family FelidaeHomotherium sp.

Fig. 29AReferred specimens. Pit B: F:AM 144637, anterior part of left

dentary with two incisors, canine, p3 alveolus, p4 and m1. Pit D: 4099,

m1 fragment. Description. The dentary (Fig. 29A) is badly weathered and

fractured and is broken below the canine and posterior to m1. The incisors are massive. Much of the canine is missing. The p3 alveolus shows that the two roots were fused; alveolar length and width are 10. 3 and 5. 5 respectively. The p4 and m1 are slightly worn; the p4-m1 length is 51. 8. The p4 has a prominent posterior accessory cusp; the tooth is 22. 0 long and 10. 3 wide. The m1 possesses an external shear facet; L m1 = 29. 0; W of anterior blade = 13. 0; W of posterior blade = 12. 6. The canine-p3 diastema is approximately 38. 7. The lingual jaw depth below p3 is 37. 2 and below m1 is 37. 9. The mental foramen is situated below the p3-p4 contact.

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FIGURE 31. Miracinonyx studeri: A, left calcaneum, 4238; B, left astragalus, 4239; C, right femur, 4234. All specimens are from Pit C.

Miracinonyx studeri (Savage, 1960)Figures 29B; 30A-C; 31A-C; 32A-D; 33A-B

Referred specimens. Pit C: 4223, right dentary with p3-m1; 4224, right maxillary with P3-P4; 4225, left maxillary fragment with P3; 4226, left dentary fragment with m1; 4227, basicranium; 4228, right posterior skull fragment; 4229, atlas; 4230, cervical vertebra; 4232, proximal right radius; 4233, distal left fibula; 4234, right femur; 4235, left femur; 4236, distal right tibia; 4237, distal left tibia; 4238, left calcaneum; 4239, left astragalus; 4240, metapodials including left mc II, right mc III, distal left mc III, left mc IV, left mc V, left mt II, distal right mt III, right mt IV, distal left mt IV,left mt V, and right mt V; 4486, 7th cervical; 4487, lumbar vertebra; 4488, lumbar vertebra; 4489, left scapho-lunar; 4490, right navicular; 4491, right ectocuneiform; 4492, first phalanx; 4101, broken first phalanx; 4493, second phalanx; 4494, second phalanx; 4495, third phalanx (claw); 4496, right cuboid. Pit D: F. AM 69255, a nearly complete left dentary with canine and p3-m1.

Description. Some of the fossil cat remains recovered from Pit C, especially the maxillary and mandibular dentitions, compare favorably with those of Miracinonyx studeri from the Cita Canyon LF described by Savage (1960; as Felis studeri). Some of the postcranial elements also approach in size and morphology some of the larger elements in the Cita Canyon collection, which may be referable to M. studeri. Because there are several cat species represented in the Cita Canyon LF, referral of the larger postcranial elements to this species is still somewhat tentative.

The upper dentition is best represented by a right maxillary fragment, 4224 (Fig. 30B), containing P3 and P4 and the single-rooted alveolus of P2. A well-developed shear facet is present on the inner surfaces of P3 and P4. The central cusp of P3 is prominent, and there is a well-developed accessory cusp in line between it and the posterior cusp. A tiny lingual accessory cusp is present between the central cusp and the anterior cusp. The protocone of P4 is low – partly the result of shear. A prominent parastyle is present and the paracone and metacone

46

FIGURE 32. Miracinonyx studeri: A, left metacarpal II, 4240a; B, right metacarpal III, 4240b; C,left metacarpal IV, 4240c; D, left metacarpal V, 4240d. All specimens are from Pit C.

47

FIGURE 33. Miracinonyx studeri: A, left metatarsal II, 4240e; B, right metatarsal V, 4240f. Both specimens are from Pit C.

48TABLE 17. Measurements (in mm) of metacarpals (Mc) and metatarsals (Mt) of Miracinonyx studeri from Red Corral Pit C (RC 4240, L=left, R=right), and modern Panthera leo (M-874 right and M-916 left).

Element Measurement RC 4240 M-874 M-916Mc II Greatest length 95. 7-L 99 102. 8

Greatest prox. transverse width 16. 8-L 20 23Greatest prox. dorsoventral ht. 24. 3-L 23 28. 4Mid-shaft transverse dia. 10. 5-L 9. 7 10. 8Mid-shaft dorso-ventral dia. 12. 5-L 11. 3 12. 6Greatest distal transverse width 16. 0-L 17 21

Mc III Greatest length 115. 7-R 110. 5 112. 4Greatest prox. transverse width 20. 4-R 22. 2 26. 2Greatest prox. dorso-ventral ht. 20. 2-R 20. 2 23. 4Mid-shaft transverse dia. 13. 1-R 11 12. 9Mid-shaft dorso-ventral dia. ` 12. 8-R 9. 7 10. 3Greatest distal transverse width 19. 2-R 18. 8 21. 9

Mc IV Greatest length 109. 6-L 105. 7 109. 5Greatest prox. transverse width 16. 2-L 17. 5 21. 3Greatest prox. dorso-ventral ht. 20. 1-L 20 23. 1Mid-shaft transverse dia. 12. 0-L 11. 4 13. 1Mid-shaft dorso-ventral dia. 12. 3-L 9. 5 10. 5Greatest distal transverse width 17. 5-L 16. 6 20. 3

Mc V Greatest length 101. 2-L 86. 4 90. 5Greatest prox. transverse width 22. 8-L 22. 4 24. 9Greatest prox. dorso-ventral ht. 22. 0-L 20. 5 23Mid-shaft transverse dia. 12. 2-L 11 13. 3Mid-shaft dorso-ventral dia. 11. 6-L 9. 9 10. 6Greatest distal transverse width 19. 2-L 16. 5 19. 6

Element Measurement RC 4240 M-874 M-916

Mt II Greatest length 125. 1-L 112. 9 119. 7Greatest prox. transverse width 20. 2-L 13. 7 18. 4Greatest prox. dorso-ventral ht. 26. 4-L 24. 3 27. 8Mid-shaft transverse dia. 13. 2-L 10. 7 13. 4Mid-shaft dorso-ventral dia. 13. 7-L 12 12. 1Greatest distal transverse width 21. 3-L 17. 1 21. 1

Mt IV Greatest length brk. -R 125. 1 130. 5Greatest prox. transverse width 14. 7-R 17. 6 19. 3Greatest prox. dorso-ventral ht. 26. 0-R 21. 7 25Mid-shaft transverse dia. 14. 6-R 13. 5 13. 6Mid-shaft dorso-ventral dia. 15. 3-R 11. 8 14. 6Greatest distal transverse width 19. 7-R 16. 5 20

Mt V Greatest length 125. 2-R 112. 2 117. 8Greatest prox. transverse width 18. 2-R 18. 5 22. 2Greatest prox. dorso-ventral ht. 13. 6-R 14. 5 17Mid-shaft transverse dia. 9. 2-R 8. 1 10. 6Mid-shaft dorso-ventral dia. 10. 8-R 10. 4 10. 5Greatest distal transverse width 17. 0-R 15 19. 2

are both well-developed and separated by an open carnassial notch. Measurements are: P2 alveolus (L = 5. 0, W = 3. 5); P3 (L = 19. 0, W = 10. 2); P4 (L = 28. 0, W across protocone and parastyle = 13. 5, W across metacone = 8. 1). The length of P3-P4 is 48. 0. A left maxillary fragment, 4225 (Fig. 30A), contains P3, the single-rooted alveolus of P2, and the posterior portion of the canine alveolus which shows that the canine was conical in shape (not mediolaterally flattened as in Dinofelis paleoonca). The left P3 (L = 19. 5, W = 11. 1) resembles the right P3 in stage of wear and cusp development. Length and width measurements of two upper dentitions of M. studeri from Cita Canyon given by Savage (1960, p. 324) are: P3 (19. 1 x 9. 5 and 18. 2 x 9. 5); P4 (28. 5 x 13. 9 and 27. 3 x 12. 6).

The lower dentition is represented by two dentaries. A right dentary, 4223 (Fig. 30C), from Pit C is that of an old individual. It contains p3-m1 and is broken across the base of the coronoid process. Most of the articular condyle is present, but the angular process is missing. The

central cusp of p3 is worn flat, a heel is present, and the two roots are exposed in the jaw. The p4 possesses a tall central cusp, a low anterior cusp, and a prominent accessory cusp between the central and posterior cusps. The m1 shows a heavy labial shear facet and a wide, V-shaped carnassial notch between the paraconid and protoconid. Measurements are given in Table 15. The ramal fossa is deep and terminates anteriorly behind m1. The anterior part of the jaw preserves part of the diastema between p3 and the canine, although the canine and alveolus are missing. Below the diastema are two dorsoventrally aligned anterior lateral mental foramina that appear to be nearly confluent because the bony bar between them has been broken. A large posterior mental foramen is situated about 10 behind the anterior pair. This foramen pattern is considered to be the most common one in pumas according to Savage (1960, p. 331-332). In addition, there is a large mandibular foramen situated about 25 behind m1 on the lingual jaw surface. There is also a left dentary fragment, 4226, which contains a broken and weathered m1. Savage (1960, p. 328) provided measurements of a mandible and lower dentition of Miracinonyx studeri, WT 1218, housed in the Panhandle-Plains Historical Museum. These measurements as well as additional ones made by the author are shown in Table 15.

The left dentary, F:AM 69255 (Fig. 29B), from Pit D, is that of a young adult and is nearly complete with c, p3-m1. Part of the ventral portion below p4 and m1 was missing and has been restored. The articular condyle is present, but part of the angular process is missing. The ascending ramus is intact. The cheek teeth are only slightly worn. The specimen is the size of 4223 from Pit C. Measurements are given in Table 15.

Postcranial elements are represented by a few vertebrae, leg bones and foot bones from Pit C. There is no duplication of elements and presumably all of the specimens are from one individual.

An atlas, 4229, is nearly complete except for the missing wings. The atlantal foramen is well-developed. Width of the occipital condylar

49fossa is 58. 0; W across the axis facets is 51. 0; and W of the neural canal is 27. 5.

A right radius, 4232, is missing the distal half. The long diameter of the proximal end is 30. 7 and the shortest diameter is 22. 3. At the broken end, the shaft measures 26. 1 x 12. 6. The radial (bicipital) tuberosity is a prominent knob. The lateral tubercle below the proximal end is well-developed as a linear ridge. Length and width of an unnumbered right radius from Cita Canyon are 31. 0 and 22. 0 at the proximal end.

A left femur, 4235, and a right femur, 4234 (Fig. 31C), are nearly complete. They were compared with the femora of a modern lion, Panthera leo, skeleton, M-874, from the collections at the University of Texas in Austin (Table 16). The Red Corral femora are slightly longer and more anteriorly bowed and the shaft is thicker anteroposteriorly. In the lion, the shaft is slender but broadens slightly from the mid-point to the proximal end but not toward the distal end. A linear muscle attachment ridge is present on the proximal lateral surface of both the Red Corral specimens and the lion. In the Red Corral femora this ridge continues distally and curves more anteriorly on the lateral surface whereas in the lion it disappears distally. The intercondylar notch is shallow and broad on the patellar surface in the Red Corral specimens but deeper, narrower, and sharply defined distally in the lion. In the Red Corral specimens, the neck connecting the head of the femur to the shaft appears to be shorter than in the lion. The left femur from Pit C matches in size a large left femur, JWT 569, in the Cita Canyon collection. Unfortunately, the proximal end of the latter is missing so that the overall length cannot be determined. However, the shaft appears to be of equal length and diameter (c. 26. 0), and the width across the distal extremity is 64. 0. Other femora in the Cita Canyon collection are smaller. Table 16 compares the measurements of the Red Corral femora with those of the modern lion, P. leo.

A right tibia, 4236, contains the distal end and most of the shaft but is missing the proximal end. A prominent ridge separates the posterior surface from the outer lateral surface of the shaft (as in the lion). At the distal extremity the grooves for the tendons of the flexor longus digitorum and tibial posticus muscles are well-defined (also as in the lion). In the lion tibia a prominent tubercle lies anteromedial to these grooves, and another lies posterior to these grooves. The same tubercles are present on the Red Corral tibia but the anteromedial one is not as prominent. The notch incising the anterior border of the distal surface is not as deep in the Red Corral specimen as in the lion tibia. Measurements of 4236 are: transverse diameter of the shaft at the middle = 28. 2; greatest transverse diameter of the distal end = 49. 3; and greatest anteroposterior diameter of the distal end = 31. 0. A right tibia, JWT 1031, from Cita Canyon matches the Red Corral specimen in size and features. The distal end measures 46. 0 by 29. 0. The distal half of a fibula, 4233, from Pit C measures 27. 4 x 13. 0 across the extremity.

A left calcaneum, 4238 (Fig. 31A), was compared with that of the lion. It measures 105. 5 in length (lion = 102. 6). The greatest width across the astragalar facets As1 and As2 at the peroneal tubercle is 36. 8. The cuboid facet has been restored on its inner border, and its greatest width measured from astragalar facet As3 to the outer side is approximately 27. 8. The greatest depth of the outer face of the calcaneum measured normal to the plantar border and to the edge of the outer astragalar facet is 41. 0. As2 and As3 are separate – bridged by a narrow ridge or crest in the lion but in the Red Corral cat, this ridge is missing. In both the lion and the Red Corral cat, As1 encroaches posteriorly on to the dorsal surface of the tuber calcis. In the lion, a short, wide tuberosity occurs dorsally on the lateral surface behind the cuboid facet (AP = 15. 2, vertical height = 8. 8). This feature is not developed in the Red Corral specimen, although a stout lateral ridge connects the cuboid facet with As1. In the Red Corral specimen, the tuber calcis is longer than in the lion but the Achilles end is not as wide. Achilles height and width are 26. 7 and 27. 7 in the lion and 25. 1and 23. 5 in the Red Corral specimen. Measurements of a smaller left calcaneum, JWT 1940, from Cita Canyon are: greatest length = 96. 0; greatest width across the astragalar facets = 34. 0; greatest depth = 39. 0; Achilles height and width of the tuber calcis are 23. 0 and 23. 0.

A left astragalus, 4239 (Fig. 31B), appears to articulate well with the calcaneum. The greatest length is 48. 0, the greatest width is 40. 0, and the width across the trochlea is 28. 0. The greatest diameter of the navicular head is 28. 0 and the minimum distance across the neck is 16. 5. The neck is narrower in the lion and the navicular head is slightly smaller. The trochlear surfaces are similar in the lion and the Red Corral specimen, and the medial surface of the inner trochlear ridge is interrupted in the middle by a muscle scar in both. Measurements

of a smaller left astragalus, JWT 1683, from Cita Canyon are: greatest length = 42. 0; greatest width = 36. 0; and width across the trochleae = 25. 0.

Four complete metacarpals and four complete metatarsals, 4240 (Figs. 32, 33), were recovered and were compared with those of Panthera leo, M-874 and M-916 (Table 17). In the left metacarpal II, the trapezoid facet, Td, is triangular in shape as in the lion but is narrower. The dorsointernal corner of Td is elevated above the rest of the facet but not as much as in the lion. The radial artery groove on the dorsal surface below the proximal end is slightly less developed than in the lion. The swelling on the dorsointernal border below the groove is about as developed as in the lion. The trapezium facet, Tm, projects slightly above the proximal border and is not as well-developed as in the lion, and it is not as distinctly separated from the tubercle below. The dorsal facet for metacarpal III is elongated obliquely as in the lion. The mid-shaft is not as inwardly bowed on its inner surface as in the lion. The distal ends are similar.

In the right metacarpal III, the dorsoexternal border of the magnum facet, Mg, is more raised than in the lion. Along the lateral border of the proximal end, Mg is more sharply separated from a lateral facet for the unciform than in the lion. The dorsal metacarpal II facet is slightly more longitudinal in dorsal view and not as internally extended as in the lion. Therefore, the groove between the dorsal and palmar metacarpal II facets appears broader and not as deep in the Red Corral specimen. In lateral view, however, the long axis of the dorsal metacarpal II facet is oblique as in the lion. The unciform facet, Un, in the fossil is larger and broader (absent in Panthera atrox). In lateral view, the shaft is thicker in dorso-palmar direction than in the lion; the distal ends are similar.

In the left metacarpal IV, the proximal end is similar to that of Panthera atrox. The palmar border is about as broad as in P. leo. The inner border of the proximal end is not as deeply notched as in P. leo. The outer border of the surface articulating with the unciform is straight and curves into the palmar border as in the modern lion. On the dorsal border, the indentation between the unciform facet and the metacarpal III facet is about as deep as in P. leo (shallower than in P. atrox). The dorsal mc III facet is similar to that of P. atrox. On the outer surface of the proximal end, the mc V facet is continuous from the dorsal to the palmar surface as in P. leo.

The left metacarpal V is longer than that of Panthera leo. The proximal surface articulating with the unciform is relatively broader near the dorsal border than in the modern lion, whereas in the latter, it tapers dorsally to appear as a narrow triangle. The inner ear-shaped projection of the proximal end, which supports a portion of the articulating surface for mc IV, is longer but less extended laterally compared to the lion. To the palmar side of this projection, the notch that indents the margin of the facet for mc IV is slightly deeper than in the lion. On the outer side of the proximal end, the tuberosity is very pronounced, as in mature P. leo. The shaft is less bowed than in the modern lion. Measurements of the Red Corral metacarpals and those of P. leo are given below in Table 17.

The left metatarsal II is not as inwardly bowed, and the mesocuneiform facet is transversely narrower and more elongated compared to the lion. The right metatarsal IV is missing the mid portion of the shaft. The proximal surface for articulation with the cuboid is narrower but less indented externally near the palmar margin compared to Panthera leo. It is more rectangular in shape front to back, whereas in the modern lion, it is broader dorsally and narrower at the palmar border. The left metatarsal V is missing the tip of the proximal end, but the right metatarsal V is complete. It is considerably longer than that of P. leo. The shaft is narrow as in the lion and about as bowed. The mt IV ventral facet is not as well-developed as in the lion, and the lateral border of the proximal surface is more raised. Measurements of the Red Corral metatarsals and those of P. leo are given in Table 17.

Several complete metacarpals and metatarsals from Cita Canyon were examined. They are from 7 to 10 shorter than the corresponding ones from Red Corral. Some are slightly wider and heavier than their counterparts, but a few are slightly narrower. One left metatarsal V is actually larger and heavier than its counterpart from Red Corral.

Remarks. Carranza-Castañeda and Miller (1996) referred a skull rostrum and mandible and several teeth from the Blancan age (~3. 6 Ma) Rancho Viejo site, Guanajuato, Mexico, to the species studeri but assigned it to the genus Felis. Measurements of the mandible, IGM 6676, are given in Table 15. They noted that the taxonomic status of this species has changed several times in recent years. It was synonymized with Miracinonyx inexpectatus by Van Valkenburgh et al. (1990). They gave a brief taxonomic history of cheetah-like cats from North

50America thus following Kurtén (1976) in resurrecting Cope’s (1895) species, “inexpectata. ”Savage (1960), however, considered Felis inexpectata (Cope) to be a nomen dubium because the type, an isolated upper canine and P4 and jaw fragments with broken p4 and m1, from the Irvingtonian age Port Kennedy Cave in Pennsylvania, does not represent sufficient material upon which to properly designate a species. Carranza-Castañeda and Miller (1996) also noted that a major problem in identification is that a lineage of pumas in North America paralleled the Old World cheetahs morphologically (Martin et al., 1977). They noted also that the specimens assigned to Miracinonyx inexpectatus by Van Valkenburgh et al. (1990) are from Hamilton Cave, West Virginia, which dates about 0. 82-0. 85 Ma., and that it seems unlikely that a single species of felid would have a chronologic range of nearly three million years. Miracinonyx has been identified from several other Irvingtonian sites and was also listed as present in the Blancan age fauna from 111 Ranch, Arizona (White and Morgan, 2005).

No doubt the taxonomic status of this felid will continue to be debated. For now I retain the species studeri but assign it to the currently recognized genus Miracinonyx. In any event, the importance of the Red Corral felid is that it provides an association of dental and postcranial elements of one individual from the same quarry site, as there is no duplication of elements. It demonstrates that this cat had long, relatively slender femora and large, stout metapodials.

Felis sp. – smallReferred specimens. Pit C: 4508, proximal left metacarpal IV.

Pit D: 4100, upper right canine fragment; 4101, a phalanx. WT Loc. 5, draw west of Pit D: 4547, proximal left metacarpal IV.

Description. The metacarpals are too small to belong to Miracinonyx studeri but are about the size of a large mountain lion. They might belong to the Blancan species Felis lacustris or F. rexroadensis which are tentatively retained in the genus Felis (sensu lato) because of the usual limitations of scarce and fragmentary fossil material that precludes assignment to one of the currently recognized cat genera. The proximal width of 4508 is 12. 6 and that of 4547 is 12. 6. The proximal depth of 4508 is 14. 2 and that of 4547 is 14. 8. The canine fragment is not diagnostic.

Order ProboscideaFamily Gomphotheriidae

Stegomastodon mirificus (Leidy, 1858)Referred specimens. Pit C: 4505, left m3; 4506, small juvenile

tusk; F:AM 103209, a partial skull, jaws, and tusks. Description. The left m3, 4505, measures about 220 long

and about 88 wide and is that of a late mature adult. There are six lophids, and all show wear but not sufficient to obliterate trefoiling. The anterior part of the tooth contains several fractures and breaks, and much of the enamel is missing on the inner and outer sides of the protolophid and metalophid and on the outer sides of the remaining lophids except the fifth, on which the enamel loop is complete. The remaining central part of the protolophid shows complex or compound trefoiling (ptychodonty). The metalophid has a compound entofoil. The remaining lophids have simple entofoils and compound ectofoils where the enamel is preserved. There is a small hypoconulid on which the enamel is missing. A small conulid is present between the trilophid and the tetartolophid. The anterior root is large and single, although the ventral part of the outer side has been broken and displaced. The tooth is slightly concave on the dorsal surface.

The skull and jaws, F:AM 103209, are large and contained within a partially opened jacket. Cheek teeth are present. Because of its large size and lack of preparation, the specimen was not borrowed for study.

Remarks. The left m3 appears to be that of Stegomastodon mirificus, the most common Blancan species in the Great Plains. Morgan and Lucas (2011) and Lucas et al. (2011) reviewed the nominal species of Stegomastodon including some no longer considered valid. They regarded S. primitivus Osborn, based on a specimen from the late early Blancan Sand Draw Lf of Nebraska, as the most primitive species of Stegomastodon characterized by cheek teeth with relatively simple trefoils, second molars with three lophs/lophids, and third molars with 5-6 lophs/lophids despite the fact, as Savage (1955, p. 66) noted, that the morphology of the S. primitivus sample described by Osborn (1936) overlaps that of the late Blancan Cita Canyon and Blanco Formation samples assigned to S. mirificus thus leading Savage (1955) to express skepticism about the validity of S. primitivus. Lucas et al. (2011) also regarded S. rexroadensis Woodburne (1961) from the early Blancan Rexroad LF of Kansas, as a junior synonym of S. primitivus. S. mirificus,

named by Leidy from the “Loup Fork” of Nebraska, is considered by Lucas et al. (2011) to encompass most known Stegomastodon specimens from late Blancan faunas whereas S. primitivus is characteristic of early Blancan faunas. They note that S. mirificus has cheek teeth that wear to double trefoils, second molars with rudimentary fourth lophs/lophids, and third molars with 6-7 lophs/lophids. The left m3, 4505, is assigned to S. mirificus based on the presence of 6 lophids and the more complex trefoiling, thus providing a good indicator for the late Blancan age of the Red Corral LF.

Based on the results of Carbon 13 isotope studies of tooth enamel in Stegomastodon from the Pleistocene of South America (e. g. Prado et al., 2001; Sanchez et al., 2003; Lopes et al., 2013), one might reasonably conclude that S. mirificus was probably a mixed feeder (C3 browse and C4 grasses).

Order PerissodactylaFamily Equidae

Nannippus peninsulatus (Cope, 1885)Figures 34H-I

Referred specimens. Pit C: 4264, upper right molar; 4265, three upper left molars; 4266, four upper tooth fragments; 4267, incisors; 4268, isolated lower teeth; UMMP 50254, upper right molar. Pit D: 4172, four upper molars; 4173, seven lower molars/premolars including three that are associated; 4174, incisors; 4175, right calcaneum; 4176, carpals and tarsals; 4200, two second phalanges. WT Loc. 5, draw west of Pit D: 4548, two lower right molars. Additional unstudied material is in the Frick Collection.

Description. This small horse (much smaller than Equus) is not abundant in the fauna and is represented primarily by upper and lower molars and premolars. No jaw material was found. Slightly worn upper molars are very hypsodont (Fig. 34H-I). In the lower cheek teeth, the metaconid and metastylid are rounded loops. Measurements are given in Table 18.

A small right calcaneum, 4175, of an immature individual lacks the posterior epiphysis. The overall length would be in excess of 67. The width across the astragalar facet is 31. 5, and the greatest anterior height is 35. 4. Measurements, respectively, of two medial phalanges, 4200, are: length = 31. 1 and 28. 2; proximal width = 24. 9 and 23. 5; proximal depth = 18. 5 and 18. 5; distal width = 22. 0 and 22. 5; distal depth = 13. 2 and 13. 0.

Remarks. Nannippus peninsulatus is one of the most characteristic Blancan mammals. It is known from the late Blancan of Florida and from numerous early and late Blancan faunas in Arizona, New Mexico, and Texas; a few localities in Kansas; and a single tooth from the Sand Draw LF of Nebraska. Some of the more notable occurrences cited by Morgan et al. (2008, p. 160-161) include the early Blancan Bear Springs, Benson, Clarkdale, and Duncan local faunas and the late Blancan 111 Ranch and Wolf Ranch local faunas of Arizona; the early Blancan Buckhorn, Williamsburg, and Tonuco Mountain local faunas and the late Blancan Pearson Mesa, Anapra, Palomas Creek, and Santo Domingo local faunas of New Mexico; and the late Blancan Cita Canyon, Hudspeth, Red Light, and Mount Blanco local faunas of Texas. Most Blancan records are from strata that date to the upper Gauss chron or older (older than 2. 58 Ma). The only well-documented late Blancan records of Nannippus younger than the Gauss/Matuyama boundary (2. 58 Ma) are Mount Blanco, Texas, and the Macasphalt Shell Pit in Florida, both of which are in reversely magnetized sediments of the early Matuyama chron (2. 16-2. 58 Ma) (Bell et al., 2004; Morgan et al., 2008). N. peninsulatus apparently became extinct sometime during this interval.

Stable Carbon 13 isotope studies of tooth enamel of Nannippus from the late Blancan of Florida indicate a grazing diet with a preference for C4 grasses although seven enamel samples indicate that a significant proportion (up to ~ 50 %) of C3 browse was probably included in the diet of some of the individuals sampled (Feranec and MacFadden, 2000, p. 162).

Equus sp. Figures 34A-G

Referred specimens. Pit C: 4269, right dentary with symphysis (missing incisors) and p2-m3; 4270, left dentary with p3-m3 (probably same individual as 4269); 4271, right dentary with p2-m3; 4295, anterior part of both dentaries with symphysis, all incisors, right canine, broken left canine, right p2 and p3, broken left p2, p3,and p4; 4296, dentary fragment with two worn teeth; 4292, isolated incisors and canines; 4293, isolated lower molars and premolars; 4294, isolated

51

FIGURE 34. Equus sp. : A, right lower dentition, 4269, Pit C; B, left lower premolar,4181, Pit D; C, left metacarpal, 4282, Pit C; D, first phalanx, 4481, Pit C; E, first phalanx, 4284, Pit C; F, second phalanx, 4482, Pit C; G, second phalanx, 4483, Pit C. Nannippus peninsulatus: H, left upper molar UMMP 50254, Pit C; I, right upper molar, 4264, Pit C.

52

upper molars and premolars; 4298, lower right molar; 4481, lower right molar; 4272, lumbar vertebra; 4273, lumbar vertebra; 4274, lumbar vertebra; 4299, distal right tibia; 4482, distal right tibia; 4275, left calcaneum; 4297, right calcaneum; 4276, right astragalus; 4277, right astragalus; 4278, left astragalus; 4279, right astragalus; 4280, patella; 4281, proximal right metacarpal; 4282, left metacarpal; 4283, 4284, 4481, three proximal phalanges; 4285, 4286, 4482-4485, six medial phalanges; 4287, distal phalanx; 4288, distal phalanx; 4289, two left naviculars and two sesamoids; 4290, splint bones; 4291, petrosal bones.

Pit D: 4181, associated lower left and right dentitions with p2-p4 and m2-m3; 4178, left dentary with p2-m3; 4182, isolated lower molars and premolars; 4183, lower deciduous premolars; 4180, associated left P2-M2 and right M2-M3; 4184, upper molars and premolars; 4179, incisors; 4186, incisor; 4185, left astragalus; 4201, left astragalus; 4202, proximal phalanx; 4203, periotic; 4204, left cuboid; 4205, splint bones.

Pit A: 4522, left tibia; 4523, proximal end of right metacarpal; 4524, carpal.

Pit B: 4513, right astragalus; 4516, right astragalus; 4517, left

astragalus; 4514, distal end of metapodial; 4512, proximal phalanx; 4515, medial phalanx; 4518, medial phalanx; 4519, medial phalanx; 4520, right ectocuneiform; 4521, magnum.

Loc. 5: 4525, associated left p2-m2 and right m1-m3; 4529, right dentary with p2-m3; 4527, associated right dp2-dp3 and left dp2; 4528, two lower left deciduous premolars; 4526, palate with right DP2-DP4 and left DP3-DP4; 4530, left tibia; 4531, distal right tibia; 4532, right metacarpal; 4533-4537, four distal ends of metapodials; 4538, 4539, 4541, 4543, four proximal phalanges; 4542, medial phalanx; 4540, associated proximal and medial phalanges; 4544, right navicular; 4545, splint bones.

Additional unstudied horse teeth and other material are in the Frick Collection and the Panhandle-Plains Historical Museum.

Description. A medium-sized horse is best represented at Pit C by several dentaries bearing complete or nearly complete dentitions. A right dentary, 4269 (Fig. 34A), bears the edentulous symphysis and p2-m3 with an occlusal length of 167. 2. A left dentary, 4270, contains the alveolus of p2 and p3-m3 with an occlusal length of 136. 5. The two jaws probably represent a single individual, as the size, shape, and wear stage of the teeth are nearly identical, and there appear to be two points of contact across the left p2 alveolus despite weathering of the broken edges. In the lower molars, the ectoflexid penetrates slightly into the isthmus between the pre- and post-flexids (further in m1 than in m2 or m3). The entoflexid between the metaconid and metastylid is broad and V-shaped. A right dentary, 4271, contains p2-m3 that are slightly more worn with an occlusal length of 170. 9. The ectoflexid in the molars just reaches but does not penetrate into the isthmus between the pre- and post-flexids, and the entoflexid is also broad and V-shaped. A mandible, 4295, contains all incisors, canines (left broken), left p2 (broken), p3, p4, and right p2-p3. Width across the incisors = 64. 0. Individual cheek tooth measurements from the above specimens as well as those of lower teeth from Pit D and Loc. 5 are given in Table 19. No maxillaries or associated upper dentitions were collected at Pit C. Numerous upper and lower molars, adult and deciduous premolars in different wear stages are present in the sample, however. In the upper teeth, the fossettes are simple, and the protocones are not greatly elongated. Two upper teeth show the development of a small pli caballin fold. The occlusal length and width of the largest upper premolar (right) are 29. 9 and 32. 5, respectively; the occlusal length and width of the smallest upper molar (left) are 24. 0 and 25. 5, respectively. The ectostyles are well-developed in the premolar. Both teeth are moderately worn. A few of the lower molars are narrower than the rest, although there is little variation in occlusal length at any given wear stage. In seven lower molars the ectostylid deeply invades the isthmus between the pre- and post-flexids. In the remaining molars in which the occlusal pattern is clearly discernable, the ectostylid just reaches the isthmus.

At Pit D, where bone preservation is poor, Equus is best represented by an associated left and right lower dentition, 4181 (Fig. 34B), lacking both m1s. The teeth are those of a young adult and are very hypsodont. The ectoflexid penetrates just to the base of the isthmus between the pre- and post-flexids in m2 but well into the isthmus in m3. The entoflexids are wide and V-shaped. A left dentary fragment, 4178, contains p2-m3 in an advanced stage of wear. In m2 and m3, the ectostylid also penetrates just to the isthmus and the entoflexid is broad and V-shaped. Measurements of 4181 and 4178 are given in Table 19. Several isolated lower cheek teeth include molars in which the ectoflexid penetrates to or into the isthmus. No maxillaries are present, but 4180 consists of an associated left P2-M2 and right M2-M3 of a very young adult. The teeth are very hypsodont and lingually curved. P4 and M3 are unerupted, and an extremely worn left DP4 was associated with the unworn P4. The protocones in the newly erupted teeth are somewhat elongated, pointed at their extremities, and possess a slight lingual indentation. However, the fossettes are simple, and the styles are not strongly developed. Several isolated upper molars show shorter protocones as well as simple fossettes. In all upper teeth present, the connection of the protocone to the protoselene is about 1/3rd of the distance from the anterior end of the protocone. Measurements of 4180 and several other upper teeth are given in Table 20.

At Locality 5, in a small draw west of Pit D, several specimens were collected, including 4529, a right dentary with p2-m3. The teeth are broken and unmeasurable, although the molars show a slight invasion of the ectoflexid. No. 4525 consists of associated lower left p2-m2 and right m1-m3 of a young adult. The ectoflexids in the molars extend to but not into the isthmus, and the entoflexids are broad and V-shaped. Measurements of 4525 are given in Table 19.

Postcranial elements were collected at all five localities and

TABLE 18. Measurements (in mm) of upper and lower teeth of Nannippus peninsulatus from Red Corral sites.

Tooth Length Width Protocone length

Pit C4264 right M1? 16. 7 15. 1 6. 14265a left M1 brkn. 17. 1 6. 34265b left M2 18. 2 17. 5 8. 54265c left M3 19. 2 15. 7 9. 5

Pit D4172a right M 19. 2 18 6. 94172b left M 19. 9 17. 5 8. 4

Tooth Length WidthMetaconid-Metastylid length

Pit C4268a left p2 19 12. 2 9. 94268b left p/m 17. 2 11 124268c left p/m 16. 5 10. 5 10. 84268d left m 19 12. 3 134268e left m 20. 2 10. 2 11. 24268f left m 19 11. 4 13. 54268g left m 17. 5 11. 8 11. 44268h left p/m 15. 7 10. 8 10. 64268i left m3 19. 5 8. 7 10. 14268j right p2 15. 8 10. 2 9. 24268k right p/m 16. 1 10. 9 10. 94268l right p/m 16. 2 10. 2 10. 74268m rightp/m 15. 5 9 114268n right p/m 17. 2 10. 6 10. 74268o right p/m 16. 5 11. 5 11. 54268p right p/m 18. 1 9. 9 10. 44268q right m3? 19. 9 10. 6 11. 54268r right m3 21. 5 8 10. 44268s right m3 21. 3 7. 4 104268t right m 15. 6 10. 1 11. 2

Pit D 4173a right p2 17 10. 3 9. 14173b right p/m 17. 1 11. 5 11. 54173c right p/m 18. 3 12 11. 74173d right p/m 18 12. 7 12. 64173e right p/m 16. 7 9. 9 9. 64173f right p/m 17. 9 10. 2 10. 34173g left p2 18 11 9

Loc. 54548a right p 18. 2 12. 1 12. 44548b right m 19. 3 10. 1 10. 9

53

presumably belong to the same species as the dentitions. These include two tibiae; two calcanea; 7 astragali; a left metacarpal, 4282 (Fig. 34C); and several phalanges (Figs. 34D-G). Measurements of these elements are given in Table 21.

Remarks. At least some of the Red Corral dentitions and isolated teeth are probably referable to Equus (Dolichohippus) simplicidens, a common Blancan horse, based on the simple fossettes and short simple protocones in the upper teeth and the fact that in some of the lower molars, the ectoflexid penetrates into the isthmus between the pre- and post-flexids, and the valleys between the metaconid and metastylid are V-shaped. E. scotti, another large horse found in Blancan and Irvingtonian faunas, is larger and has more complex fossettes and longer protocones on the upper molars and lacks the deep ectoflexids on the lower molars. Equus cumminsi is a much smaller horse and quite rare in Blancan faunas and is still poorly known.

The calcanea and astragali seem smaller and the metacarpals and the proximal phalanges more slender compared with measurements of similar bones assigned to Equus (D. ) simplicidens from other Blancan faunas. The left metacarpal, 4282 (Fig. 34C), has a length to width ratio of 5. 65 which is close to the minimum ratio given by Winans (1989) for her E. francisci group and suggests the possible existence of a stilt-legged horse in the fauna such as E. calobatus, which is based on a long and slender metacarpal but lacks an associated skull or dentition. It seems likely that there is only one large horse in the Red Corral LF, however, and that the postcranial elements belong to the same species as the dentitions. Morgan et al. (2008) recognize several large to medium-sized horses from the Blancan age Pearson Mesa LF in the Duncan Basin in southwestern New Mexico – some of which are only assigned to generic level.

Order ArtiodactylaFamily Tayassuidae

Platygonus sp. Figure 35A

Referred specimens. Pit C: 4250, upper canine. Pit D: 4121, tooth fragments. A dentary fragment with two teeth and an isolated molar and

incisor are in the Frick Collection of the American Museum of Natural History but were not examined.

Description. The upper canine (Fig. 35A) shows a prominent anterior wear facet and is broken across the tip. The greatest anteroposterior dimension is 21. 9, and the greatest width is 12. 9.

Remarks. The Red Corral fossils are too fragmentary for species identification, although they very likely belong to Platygonus bicalcaratus, the most common Blancan species of peccary.

Family CamelidaeCamelops sp. Figure 35D

Referred specimens. Pit C: 4251, left dentary with dp3-dp4 and m1-m2. WT Loc. 5, draw west of Pit D: 4549, left radius-ulna; 4546, proximal end of a proximal phalanx.

Description. Remains of this camel are rare in the fauna. The dentary, 4251, is that of a young individual (Fig. 35D). It is broken anterior to the dp3 and behind m2. A detached portion of the ascending ramus and coronoid process was also found. The rooted dp3 and 3-cusped dp4 are much worn and were about to be shed. The m1 is fully erupted; the m2 is erupted, but there is little or no wear on the posterior lobe. Occlusal tooth measurements are: dp3 = 15. 5 x 12. 4; dp4 = 49. 7 x 20. 6 (across 3rd lobe); m1 = 42. 7 x 17. 8; m2 = 48. 9 x 20. 5. Medial jaw depth below dp4 is 50. 7 and below the posterior lobe of m2 is 82. 5.

The left radius-ulna, 4549, is missing the ulnar process. The length of the complete radial portion is 470. The greatest width of the proximal end across the lateral tuberosity is 81. 5. The width of the proximal articular surface is 75. 0, and the width of the distal articular surface is 79. 0. The greatest width across the distal end is 88. 4. The distal interosseous foramen is small. The proximal phalanx, 4546, is broken. Width and depth across the proximal end are 35. 2 and 33. 5, respectively.

Remarks. Of the three best known genera of Blancan camels, the dentary and radius most closely match the genus Camelops in size. They are too large to be those of Hemiauchenia and too small to be those of Gigantocamelus. Although remains of large camels are fairly common in many Blancan faunas, identification of Camelops species is difficult when based on lower jaws alone.

Hemiauchenia cf. blancoensis (Meade, 1945) Figure 35B

Referred specimens. Pit B (WT Loc. 3): 4511, first phalanx. Pit C: 4252, partial left dentary with m1-m3; 4253, isolated lower teeth; 4254, upper premolar; 4255, four incisors; 4256, complete proximal phalanx; 4257 and 4258, distal ends of two metapodials; 4259, distal end of proximal phalanx; 4260, fibula; 4501, distal right tibia epiphysis; Tentatively referred: 4261, left calcaneum; 4480, right calcaneum; 4262, left astragalus; 4263, right astragalus; 4497, left cuneiform; 4498, left cuneiform; 4499, right unciform; 4500, scaphoid. Pit D: 4206, six incisors. Loc. 5: 4546, proximal end of proximal phalanx. Additional material from Pits A, B, C, and D is in the Frick Collection of the American Museum of Natural History but was not examined.

Description. A small llama is represented at Pits B, C, and D by fragmentary material. A partial left dentary fragment, 4252 (Fig. 35B), from Pit C is that of an old individual. The teeth are sufficiently worn so that no trace of the anterior external buttress exists on m2, although one is present on m3. The posterior lobe of m1 and complete m2-m3 are present. Measurements are: m2 = 27. 8 x 16. 4; m3 = 38.

TABLE 19. Measurements (in mm) of lower teeth of Equus sp. from Red Corral sites. L = length; W = width. Dentition p2 p3 p4 m1 m2 m3

L W L W L W L W L W L WPit C

4269 right 31. 8 18 28. 2 19. 8 28. 1 19. 4 25. 5 17. 6 24. 5 16. 9 27. 7 15. 44270 left NA NA 28 19. 4 27. 8 19. 4 24. 8 17. 5 24. 5 16. 6 27. 3 15. 24271 right 32. 5 17. 2 29. 3 20. 5 28. 2 19. 5 25 17. 1 26. 2 15 29 14. 64295 28. 4 18. 9 26. 8 18. 9 26. 5 19 NA NA NA NA NA NA

Pit D4181 left 35. 3 17. 8 29. 9 16. 2 32. 8 20. 5 NA NA 27. 8 17. 5 24. 8 144181 right 35. 6 17. 8 29. 7 16. 2 32. 6 20. 4 NA NA 27. 5 17. 3 24. 7 144178 left 33 17. 2 28. 3 19. 1 26. 4 19. 4 23 17. 4 25. 7 18. 9 34. 6 15. 6

Loc. 54525 left 30 16. 8 28. 6 20 28. 8 brk 27. 5 17. 8 31. 4 16 NA NA4525 right NA NA NA NA NA NA 27. 5 17. 7 31. 6 15. 9 unworn

TABLE 20. Measurements (in mm) of upper teeth of Equus sp. from Red Corral Pit D.

Tooth Length Width Protocone length

Pit D4180 left P2 39. 6 26. 6 9. 54180 left P3 31. 5 26. 7 14. 54180 left P4 31. 2 27. 1 16. 24180 left M1 29. 9 27. 6 13. 94180 left M2 30. 3 24. 2 15. 1

4184a left P3 32. 4 30. 7 164184b left M1 or M2 28 28 11. 84184c left M3 28. 5 25. 1 15. 44184d left M3 28. 7 23. 5 16. 3

54

TABLE 21. Measurements (in mm) of postcranial elements of Equus sp. from Red Corral sites. Abbreviations: L = length; W = width; D = depth; Prox. = proximal; Dist. = distal.

Bone element L Prox. W Prox. D Shaft W Dist. W Dist. DMetacarpal 34282 left Pit C 243 42. 9 28. 6 29. 8 40. 1 29. 14281 right Pit C >38. 9 29. 94532 right Loc. 5 44. 2 32. 2 284523 right Pit A 46. 4 33. 2

Dist. Metapodial 34514 Pit B 46. 2 31. 34533 Loc. 5 30. 1 42. 2 32. 44534 Loc. 5 47. 4 36. 64535 Loc. 5 40. 2 31. 74536 Loc. 5 37. 3 304537 Loc. 5 40 29

Prox. Phalanx4512 Pit B >73 49 >33. 4 30 34 20. 14283 Pit C 76. 6 39. 5 27. 9 brk. brk. 18. 94284 Pit C 72. 5 41 28. 8 25. 1 33. 2 19. 94481 Pit C 74. 8 46. 8 31. 9 26 35. 3 21. 84202 Pit D >78. 2 brk. brk. 33. 1 brk. brk. 4538 Loc. 5 79. 2 43. 8 29. 5 25 34. 6 20. 14539 Loc. 5 82 brk. 28. 1 29. 4 40. 7 21. 54540a Loc. 5 78. 9 brk. 34. 7 30. 7 39. 5 23. 54541 Loc. 5 71. 9 48 33. 8 29. 6 33 19. 2

Medial Phalanx4515 Pit B 47. 5 51. 1 34. 6 47. 4 28. 94518 Pit B 39. 7 38. 6 28. 3 37. 2 22. 54519 Pit B 40. 7 brk. 29 36. 5 >22. 54285 Pit C brk. brk. 26. 8 41. 6 23. 44286 Pit C 38. 3 38. 7 27. 1 32. 6 21. 24482 Pit C 43 43. 7 29. 3 38. 7 254483 Pit C 41. 2 39 25. 9 33. 8 19. 64484 Pit C 40. 1 40 26. 6 36. 9 23. 54485 Pit C 38. 5 41. 3 26. 5 37. 8 20. 54540b Loc. 5 47. 2 46. 6 30. 2 42. 2 25. 44542 Loc. 5 44 44. 6 30. 5 36. 6 24. 2

Distal Phalanx4287 Pit C 52. 4 40. 1 facet4288 Pit C 44. 3 34. 3 facet

Tibia4522 left Pit A 69. 2 474530 left Loc. 5 47. 5 74 50. 7

Calcaneum4275 left Pit C 103. 8 46 48. 2 31 40. 14297 right Pit C 104. 8 46. 5 46. 3 31. 6 c. 47. 8

Astragalus4513 right Pit B 55. 3 42 facet4516 right Pit B 59. 4 c. 49 (brk)4517 left Pit B 54 44. 1 facet4276 right Pit C 61. 2 49. 6 facet4277 right Pit C 53. 3 37. 2 facet4278 left Pit C 56. 7 44. 6 facet4279 right Pit C 59. 5 48. 8 facet

55

FIGURE 35. Platygonus sp. : A, upper right canine, 4250, Pit C. Hemiauchenia cf. blancoensis: B, left dentary, m1-m3, 4252, Pit C. Capromeryx sp. : C, left m3, UCMP 43393, Pit C. Camelops sp. : D, left dentary, dp3-dp4, m1-m2, 4251, Pit C.

1 x 15. 5. Other isolated lower teeth and tooth fragments, 4253, and an upper premolar, 4254, are of comparable size. The lower teeth are in various wear stages, and several possess the llama buttresses. Four small incisors, 4255, are referred. Measurements of a complete proximal phalanx, 4256, are: L = 91. 3; proximal W and depth = 26. 2 and 26. 7; distal W and depth = 22. 0 and 19. 9. Two calcanea and two astragali are tentatively referred. They appear to be too small to be those of Camelops judging by measurements given by Webb (1965) for Camelops hesternus. According to measurements given by Breyer (1974), the calcanea appear to be about the size of those of Tanupolama (now Hemiauchenia) from Gordon-Hay Springs-Rushville, Nebraska. However, the astragali appear to more closely resemble in size those of Camelops from Broadwater A, Nebraska, and are larger than those

of Tanupolama (= Hemiauchenia) from Broadwater A, Lisco B, and Gordon-Hay Springs-Rushville, Nebraska. Measurements of the Red Corral calcanea are: 4261 (left):L = 130. 0, W across astragalar facet = 48. 5, greatest anterior height across parasustentacular facet = 55. 2, posterior W and height = 32. 7 and 38. 0 respectively; 4480 (right juvenile lacking posterior epiphysis): W across astragalar facet = 40. 5, greatest anterior height across parasustentacular facet = 45. 9. Measurements of the Red Corral astragali are: 4262 ( left): Length (lateral = 81. 2, medial = 71. 8, minimum = 60. 7) and distal width = 53. 8; 4263 (right): Length (lateral = 79. 0, medial = 72. 2, minimum = 59. 5) and distal width = 52. 5.

Remarks. The Red Corral dentary and teeth compare favorably with those of the type of Hemiauchenia blancoensis in size and

56development of the anteroexternal buttresses. Hemiauchenia is the most frequently occurring species of llama in Blancan faunas of the United States. Stable Carbon 13 isotope values in tooth enamel studies of Hemiauchenia in Florida indicate a preference for a C3 browse diet in Blancan time but with a higher proportion of C4 grasses through Irvingtonian and Rancholabrean time during the Pleistocene (Feranec and MacFadden, 2000; Feranec, 2003; Kohn et al., 2005; and Yann and DeSantis, 2014).

Family AntilocapridaeCapromeryx sp.

Figures 29D, 35CReferred specimens. Pit C: UCMP 43393, left m3; 4503, molar

fragment; 4504, astragalus. Pit D: 4119, isolated teeth; 4120, broken phalanx; F:AM 117078, left dentary with p2-m3 (broken). An upper molar from Pit C and an isolated right m3 from Pit D are in the Frick Collection of the American Museum of Natural History but could not be found for study.

Description. The left m3, 43393 (Fig. 35C), from Pit C is approximately 34 high. The occlusal length is 16. 0 and the occlusal width is 5. 0. The left dentary, 117078, from Pit D (Fig. 29D) is broken across m3 and the ascending ramus is missing. The occlusal length of p2-m2 is 37. 5. The length and width of the individual lower molars in the dentary are m1 = 9. 5 x 5. 5, m2 =11. 0 x 6. 3 and m3 = 15. 5 est. x 6. 3 (posterior loop is missing). Estimated length of p2-m3 is 53. 5. Lingual jaw depth below m1 = 19. 5 and below anterior of m3 = 27. 2. Maximum jaw width at m2 = 9. 3 and at m3 = 10. 9. Tooth measurements are given in Table 22.

Remarks. Antilocaprid remains are usually uncommon but widely distributed in Blancan faunas of the western United States. Fossils usually consist of isolated teeth, jaw fragments, and post-crania and are listed as antilocaprid indeterminate, or sometimes as Capromeryx sp. Horn cores, necessary for species identification, are rarely found. Two species based on horn cores are known from Blancan faunas in the United States. C. tauntonensis, a larger species, based on a cranium with the lower portion of the horn cores and associated teeth from the late early Blancan Taunton LF of Washington was described by Morgan and Morgan (1995). C. arizonensis, a smaller species, is based on a left horn core and cranial fragment from the late Blancan 111 Ranch LF of Arizona (Skinner, 1942). The premolars of FM 117078 are shorter but wider than those associated with the type of C. tauntonensis, but the first and second molars closely match in size those of the Taunton sample. The two m3s from Red Corral are shorter but comparable in width to those in the Taunton sample. Jimenez-Hidalgo et al. (2004) referred some isolated teeth from Guanajuato, Mexico, to C. tauntonensis, although horn cores were absent. Morgan et al. (2011) gave a brief description and measurements of isolated teeth from two Blancan faunas in New Mexico but assigned them only to genus. Table 22 gives comparative measurements of these teeth.

Family Cervidae

Genus and species indeterminateA 3-inch antler fragment without tines, UCMP 43405, from Pit C

is indistinguishable from that of Odocoileus, the white-tailed or mule deer, but is inadequate for even generic assignment. It may represent an extinct genus of cervid.

AGE AND CORRELATIONSeveral methods of more finely subdividing the Blancan in an

attempt to achieve better temporal resolution have been proposed over the last 40 years. As noted by Bell et al. (2004, p. 252) “most of them rely on the first and last appearances of certain mammalian taxa in specified stratified sequences or isolated localities. These appearances reflect immigration and extinction events and progressive species evolution within particular lineages. Such efforts may be hampered by problems of provinciality. Latitudinal, regional, elevational, and ecological factors lead to faunal provincialism that, together with the lack of radiometric and paleomagnetic control, can make correlation of faunas difficult. Despite such difficulties, some progress has been made in dividing the Blancan, although to date no single method or proposal is universally adopted or considered universally applicable. ”

Several attempts have been made to establish arvicoline rodent zones for the Blancan and Irvingtonian (L. D. Martin, 1979; Repenning, 1987; R. A. Martin, 2003). In recent years, increasing interest has been focused on the second phase of the Great American Biotic Interchange (GABI) between North and South America. Some workers (e. g. Morgan, 2008) define the late Blancan in temperate North America as beginning with the appearance of certain South American immigrants such as the xenarthrans Eremotherium, Paramylodon, and Glyptotherium and the rodents Neochoerus and Erethizon in faunas in the southeastern and/or southwestern United States at about 3. 0 Ma (first appearance of interchange mammals in the southwestern United States). Early Blancan faunas would date between about 4. 9 and 3. 0 Ma, whereas late Blancan faunas might date as late as 1. 8 Ma at the end of the Olduvai subchron. In terms of the paleomagnetic time scale, Blancan faunas would span the later part of the Gilbert reversed chron, all of the Gauss normal chron (3. 58-2. 58 Ma) and the early part of the Matuyama reversed chron. Another perspective suggests that the Blancan-Irvingtonian boundary be set at 2. 0 Ma, coincident with the Microtus immigration event on the Central Great Plains (Martin et al., 2008; Martin and Peláez-Campomanes, 2014), bounded below by the Huckleberry Ridge ash (2. 11 Ma) and above by the Olduvai subchron (1. 95 Ma) in the Borchers Badlands of Meade County, Kansas.

Assuming that sediments containing the Red Corral LF were deposited near the second phase of the GABI, the fauna probably falls near the beginning of the late Blancan (contra early Blancan in Janis et al., 1998, p. 637, SP1G; Janis et al., 2008, p. 713, SP1G). Paramylodon cf. garbanii is present based on a single tooth from Pit B and a left dentary containing the last two teeth from Pit C. However, no remains of Glyptotherium have been found in the fauna. Both taxa are present in the upper level of the Cita Canyon LF about 80 km (50 miles) to

TABLE 22. Measurements (in mm) of lower teeth of Capromeryx from Red Corral sites and other Blancan local faunas. Abbreviations: RC = Red Corral; F:AM = Frick American Museum; UC = Univ. California; WA = Washington; Mex. = Mexico; T or C = Truth or Consequences; A-P = Arroyo de la Parida; NM = New Mexico. L = length; W = width.

Tooth RC Pit D RC Pit C Taunton, WA. Guanajuato, Mex. T or C, NM A-P, NMF:AM 117078 UC 43343 N OR (Mean) N OR (Mean)

p2 L 4. 3 3 5. 0-5. 7 (5. 4) 2 4. 1-4. 2 (4. 15) p2 W 3 3 2. 5-2. 8 (2. 7) 2 2. 2-2. 4 (2. 3) p3 L 6. 3 3 7. 6-8. 0 (7. 8) 4 5. 6-7. 1 (6. 35) p3 W 3. 8 3 3. 2-3. 5 (3. 3) 4 3. 4-3. 6 (3. 47) p4 L 7. 5 4 8. 4-9. 2 (8. 8) 8 7. 6-9. 6 (8. 53) 9. 1 p4 W 4 4 4. 1-4. 6 (4. 3) 8 4. 0-4. 9 (4. 46) 4. 2 m1 L 9. 5 4 9. 1-10. 4 (9. 8) 5 8. 5-9. 5 (8. 9) m1 W 5. 5 4 5. 0-5. 7 (5. 3) 5 5. 2-5. 5 (5. 36) m2 L 11 6 11. 4-12. 7 (12. 0) 5 10. 3-11. 6 (10. 88) 12. 2 m2 W 6. 3 6 5. 1-6. 4 (5. 6) 5 5. 7-6. 3 (5. 9) 5. 9 m3 L c. 15. 5 16 5 17. 7-18. 9 (18. 4) 6 16. 7-17. 8 (17. 0) 17. 9 15. 7 m3 W 6. 3 5 5 5. 0-6. 2 (5. 8) 6 5. 8-6. 3 (6. 11) 6 5. 6

57the southeast of Red Corral, but neither of these genera have been found in Blancan faunas further north in Kansas. The Red Corral LF contains several characteristic taxa that are restricted to the Blancan but range throughout most or all of that age. These include Procastoroides sweeti, Sigmodon minor, Borophagus diversidens, Canis lepophagus, and Nannippus peninsulatus. Present also, however, are several taxa which first appear during middle to late Blancan time. These include Miracinonyx (Savage, 1960), Sylvilagus (White, 1991), and Stegomastodon mirificus (Lucas et al., 2011). Bell et al. (2004, p. 244-245) provide an excellent temporal range chart that includes many key genera found in Blancan faunas. Unfortunately, radiometrically datable ash beds which could provide supporting data for age assignment are lacking in the Red Corral stratigraphic section despite the fact that the section is fairly thick (about 60 meters).

Lindsay et al. (1975) reported the results of paleomagnetic sampling of the stratotype and related sequences of Hemphillian, Blancan, and Irvingtonian faunas in Texas and Kansas. They found the sediments at some sites, particularly in the Red Corral section, to be weakly magnetized and only partially stable to alternating fields. Nevertheless, the Red Corral section appears to include three normal events that Lindsay et al. (1975) correlated with the Gauss chron, and based on the mammalian fauna, in particular the rodents, this assessment is consistent with the replacement chronology of Blancan mammalian assemblages from the Meade Basin of Kansas (Martin and Peláez-Campomanes, 2014).

The Red Corral section is relatively thick at about 60 meters (200 ft). Paleomagnetic sampling of sediment from the fossil-bearing level at Pit C yielded a normal polarity result. A questionable reversed polarity result was obtained on sediment 5 meters (16 ft) below the fossil level and a normal polarity result was obtained about 25 meters (80 ft) below Pit C at the bottom of the hill. At Pit D, a sample taken from the fossil-bearing, papery maroon shales gave a very weak but possibly normal polarity reading, and a sample from just above in the unfossiliferous brown clay gave a reversed polarity result. About 25 meters (80 ft) higher in the section near the upland surface, two samples yielded a normal polarity result. Lindsay et al. (1975) tentatively placed the Red Corral LF within the middle normal unit of the Gauss (3. 22-3. 11 Ma) between the Mammoth and the Kaena subchrons – earlier than the Cita Canyon LF of Texas and the Sanders LF of Kansas but later than the Benson LF of Arizona and the Rexroad Locality 3 LF of Kansas. It should be emphasized that this placement was tentative, and that more magnetic samples and/or more fossils are needed to determine the magnetic polarity limits of the Red Corral quarries.

Taylor (1960) noted that the molluscan fauna from Pit D was similar to that at Rexroad Locality 3 in Meade County, Kansas, 235 km (146 miles) to the northeast. The fauna also shares several fossil mammals with Rexroad Loc. 3 including Sorex taylori and Scalopus (Hesperoscalops) rexroadi. Other mammal species are like those found in the younger Blancan Sanders and Deer Park local faunas in Meade County. In particular, the recognition of Sigmodon minor /medius at Red Corral rather than the smaller S. m /minor is important as S. minor experienced a dwarfing episode just prior to its extinction in the Meade Basin of Kansas (Peláez-Campomanes and Martin, 2005). On the other hand, the Neotoma and Onychomys specimens are more similar to those from Arizona faunas. Unfortunately, arvicolids (microtines), which are so useful for biostratigraphic zonation in the Great Plains, do not occur in the Red Corral LF. They are found, however, in the upper level of the Cita Canyon LF along with Glyptotherium and Paramylodon 80 km (50 miles) to the southeast. It would seem that such differences between these two faunas are more likely due to differences in geologic age rather than climate/environment, given the short geographic distance and latitude separating them. The upper Cita Canyon LF occurs in the upper normal polarity part of the Gauss magnetic chron just below the Gauss-Matuyama boundary at 2. 58 Ma. Thus, the Red Corral LF probably dates between the first arrival of Paramylodon at about 3. 0-3. 2 Ma and the Gauss-Matuyama boundary at 2. 58 Ma. [See discussion below about Hudspeth and Red Light LFs]

PALEOECOLOGY AND CLIMATETaylor (1960) suggested, based on the abundance of the mollusks

Physa anatina Lea, Gyraulus parvus (Say), Promenetus umbilicatellus (Cockerell), and Stagnicola bulimoides techella Haldeman, that the local habitat at Pit D was a shallow pond fluctuating annually and with thick submerged vegetation. He noted that Ferrissia rivularis was rare, but that it requires permanent water. He postulated that probably the pond was a lagoon or oxbow lake near a permanent stream. Strobilops,

a land snail, though rare, nevertheless indicated the presence of woodland and moist humus, but since there were so few land snails and most of those were so scarce, this habitat was probably not close to the site of deposition.

Hibbard (1941d) described the paleoecology of the Blancan age Rexroad LF from Meade County, Kansas, based on fossils from his localities 1, 2, and 3. Later studies showed that this fauna is not a single contemporaneous unit. . As understood by Hibbard (1941d, p. 88-89) the Rexroad mammalian fauna at that time contained 37 identified genera and 32 identified species. The faunal list included Pliolemmus antiquus and Pliopotamys meadensis which Hibbard recognized might be from another fauna because they did not occur at Localities 2 and 3 but only at Locality 1. The fauna at Locality 1 was later shown to be younger and became known as the Deer Park LF. The animals in the Rexroad faunal list were presumed to have lived together in the area during the Pliocene, because none of the fossils showed evidence of having been re-worked or transported any great distance before deposition. Hibbard grouped the fossil mammals into several communities based upon the adaptive characters presented by them and upon the known habitats of living species of genera represented in the fauna. He recognized an upland grass community (5), a semiaquatic community (2), a meadow (3) and marsh (2) community, a forest community, and a valley slope community (4).

Hibbard’s community model was refined by Skinner et al. (1972) when they established a set of habitat communities for the Sand Draw LF in north-central Nebraska. They postulated the existence of (1) stream-bank and lake-bank communities, (2) marsh and semiaquatic communities, (3) savanna valley communities, (4) valley slope communities, and (5) upland communities. These communities were again modified and utilized by Eshelman (1975) in his analysis of the White Rock LF in north-central Kansas. He recognized a permanent water habitat, a stream-river habitat, a lowland meadow-savanna habitat, a valley slope habitat, and an upland prairie habitat.

More recent studies suggest that these community models are too simplistic, inaccurate, or inadequate for several reasons. First, a good pollen record is needed to establish vegetation patterns and such evidence is usually lacking. Second, good geologic data is needed to establish whether a depositional site is fluvial, lacustrine, or paludal. Third, as noted by R. A. Martin (written communication, 2015), the combination of heteromyids, ground squirrels, grasshopper mice, harvest mice, and badger shows that the predominant habitat was a prairie mosaic of some kind, at least slightly upland from the more mesic communities but this could have been as little as 2-3 m up from a stream or lake bank. Such terrains can be seen in the High Plains today. Fourth, large mammals have large home ranges and freely traverse all habitats and will use streams or ponds in lowland habitats as waterholes. Furthermore, as pointed out by R. A. Martin (written communication, 2015), “large mammals are also opportunistic and will take whatever energy is available anywhere they can get it. The same is true for the small mammals, but as they are more stenotopic they do provide more information. ”

The habitat at Pits A, B, and C appears to have been a low energy stream bounded by a prairie mosaic. The sediments from which the fossils were collected were gray to buff fine silty sands and clays. Many of the fossils excavated here were isolated remains of large or medium-sized animals such as horse, camel, stegomastodont, and coyote, plus some dental and postcranial remains of the large cat, Miracinonyx studeri, which must have died near the site of deposition at Pit C. The absence of water birds, frog, pond turtles, water snake, beaver, and aquatic snails and the near absence of shrews indicate the absence of pond, lake, or marsh conditions at these sites. The nearby prairie mosaic habitats are represented at Pit C by an abundance of jaws, teeth, and a few postcranial bones of small rodents such as Geomys, Prodipodomys, Perognathus, ground squirrels, Bensonomys, Peromyscus, Reithrodontomys, Onychomys, and Neotoma, and the leporid Hypolagus concentrated in a small layer at the top of Pit C from which 12 tons of matrix were screen washed. Predation by owls may have been responsible for their abundance at the site although no actual fossil owl pellets were found. The cotton rat, Sigmodon minor /medius, was the most abundant species collected at Pit C (at least 40 individuals). Its presence indicates that some kind of mesic or semi-mesic lowland environment was present. Sigmodon is considered a grazer and today can be found in all kinds of grassy habitats along streams, not 2 m from slightly upland, drier prairie habitats. The modern species, Sigmodon hispidus, ranges today throughout much of the southern United States and into northeastern most Mexico occurring as far north as northern

58Kansas and Missouri. It is found today in southwestern Kansas and the central and eastern Texas Panhandle.

The habitat at Pit D appears to have consisted of a pond, small lake, or stream surrounded by marsh grasses. Fossils, mostly microvertebrates, were recovered by screen washing 28 tons of matrix from a papery maroon shale unit. An aquatic environment is indicated by the presence of ictalurids, frog, pond turtles, water snake, coots, rails, duck, and heron as well as many of the mollusks. Moreover, the water was sufficiently deep to accommodate the beaver, Procastoroides sweeti. The most abundant mammal recovered at the site is the cotton rat, Sigmodon minor /medius, (represented by at least 139 individuals) which would have lived in the nearby bordering grassy habitat. According to Hibbard (1941d), Sigmodon was the third most abundant species collected from the Rexroad LF (localities 2 and 3).

The second-most abundant species collected at Pit D is the shrew, Sorex taylori, which is represented by 50 dentaries (at least 27 individuals) whereas only one toothless dentary was collected at Pit C. According to Hibbard (1941d, 1953a), Sorex taylori was the most abundant species collected from the Rexroad LF (localities 2 and 3) and was a moist, lowland dweller. Today, the majority of Sorex species live along streams and marshes. The genus reaches northern Kansas but does not extend to the Texas Panhandle today. The closest points of known occurrence are northeastern Kansas, the edge of the Rocky Mountains in eastern Colorado (Frey and Moore, 1990), and central New Mexico (Wilson and Reeder, 2005). Sorex taylori also appears to have lived along streams and marshes. If so, it would seem to indicate that the region of southwestern Kansas and the Texas Panhandle enjoyed lower summer temperatures and slightly more humid conditions in the Pliocene compared to conditions in the region today.

As noted above, it is significant that no remains of arvicolid rodents such as voles, lemmings, and muskrats were recovered at any of the Red Corral sites. Such animals today are primarily northern or boreal forms. The Red Corral LF at that time may have been too far south and climate conditions not sufficiently cool and moist for such species, although it should also be noted that remains of muskrat, vole, and lemming were recovered from the slightly younger Cita Canyon LF about 80 km (50 miles) to the southeast (Schultz, in prep. ). Dalquest (1978) reported the vole, Ogmodontomys, from the early Blancan Beck Ranch LF near Snyder, Scurry County, Texas, about 354 km (220 miles) southeast of the Red Corral localities. Ogmodontomys was also the second most abundant mammal species at the Rexroad Locality 3 site. Arvicolids were also in Arizona during the Blancan and, in the early Blancan, they were at Yepomera in Mexico. Consequently, Red Corral time represents a different sampling interval from Beck Ranch and Cita Canyon. Arvicolids are also absent from the Blanco (Meade, 1945; Dalquest, 1975), Hudspeth (Strain, 1966), and Red Light (Akersten, 1970) late Blancan local faunas. Thus, the faunal evidence strongly suggests that there were significant climatic fluctuations during the Blancan.

ACKNOWLEDGMENTSField and laboratory research for this study was funded by grants

from the Killgore Research Center at West Texas State University (now West Texas A&M University). Appreciation is expressed to the University and the Killgore Research Center for providing laboratory space and equipment and a field vehicle for transporting tons of sediment to be screen washed. The author is indebted to Foy Proctor, ranch owner, and Junior Hays, ranch foreman, who graciously granted permission to collect fossils on their ranch. Members of the 1966, 1967, 1968, and 1969 field crews who assisted in the collecting, sacking, carrying, and screen washing of fossiliferous matrix include Bob T. Griffin, H. Steve Saylor, Darryl W. Maddox, Jerry D. Whittaker, James E. Couzzourt, David M. Boothe, Byron L. Nesbitt, Nicholas Petruccione, Joyce E. Mayfield, Murray E. Mayfield, Donald Backstrom, Mark Watkins, Ronald D. Sanders, James C. Meeks, Douglas C. York, Larry Wooten, John Curtis, Rick Condron, Douglas M. Baker, Willie Kay Farmer,and Virginia Essary. Pen and ink line drawings of fossil specimens were done by Bob T. Griffin, Phil A. Bandy, and Christina Morian. Appreciation is also expressed to a colleague, Gary Barbee, and to the university’s IT Services, especially Lacy Harris, Caitlin Lamberson, and Kali Arredondo, for technical assistance with computer scanning into TIFF files all of the photographs and tables used in this report.

The author is indebted to the University of California Museum of Paleontology and to the University of Michigan Museum of Paleontology and Museum of Zoology for the privilege of examining fossil and recent specimens in their care and for the loan of selected specimens for comparisons and inclusion in this study. The late Malcolm

McKenna of the American Museum of Natural History Division of Vertebrate Paleontology provided a faunal list and the privilege of examining some of the fossil specimens in the Frick Collection early in the study, and the author wishes to thank the museum for the recent loan of selected specimens from the Proctor Ranch sites and for permission to include descriptions of them in this publication. The author is also indebted to the following institutions for the loan of specimens in their care used for comparison purposes: the University of Kansas for the loan of rodent fossils from southwest Kansas; Texas Tech University for the loan of fossil Sigmodon and Hesperoscalops specimens from the Blanco LF; Midwestern State University for the loan of Hesperoscalops specimens from the Beck Ranch LF; the University of Nebraska for the loan of the type specimen of Hesperoscalops mcgrewi; the University of Texas at Austin for the loan of the skull and skeleton of the modern lion for comparison with specimens of Miracinonyx studeri; and the Panhandle-Plains Historical Museum for in house access to specimens from the Cita Canyon LF.

Appreciation is expressed to the following individuals for their aid in identification of fossil material and comments on the text. Robert Weigel of Illinois State University examined the fossil bird specimens and provided preliminary identifications. The late J. Alan Holman of Michigan State University provided preliminary identifications of the fossil amphibians and reptiles in the fauna, and Gerald Smith of the Museum of Paleontology at the University of Michigan identified the fish as belonging to the ictalurid group. Nicholas J. Czaplewski and Jon Baskin offered comments on the identification of the bat jaw and the Bassariscus molar, respectively. The late John A. White studied and identified the rabbit fossils and provided the author with camera lucida drawings of the diagnostic teeth. Colleagues Robert A. Martin, Nicholas J. Czaplewski, and Xioaming Wang critically reviewed all or parts of the manuscript and offered many helpful comments. Above all, the author is indebted to and greatly appreciative of the late Claude W. Hibbard, who provided much encouragement and helpful comments early in the study.

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the red corral (proctor ranch) local fauna (pliocene

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