diversity of fishes iii. phylum chordata –superclass agnatha class pteraspidomorphi † class...
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• Phylum Chordata– Superclass Agnatha
•Class Pteraspidomorphi †•Class Myxini (?)•Class Cephalaspidomorphi
– Superclass Gnathostomata•Class Placodermi †•Class Chondrychthyes •Class Acanthodii †•Class Sarcopterygii•Class Actinopterygii
Fish Taxa Diversity
Superclass Gnathostomata (still)
• Class Acanthodii † (“spiny sharks”)
– Cartilaginous skeletons with ossified pieces & characteristic spines
– Pelagic habitat (FW & SW)– Considered sister group of bony fish
Superclass Gnathostomata
• Class Sarcopterygii (lobed fins)– Coelacanths and lungfishes– Osteolepimorphi †
• Class Actinopterygii (ray fins)- Ray finned fishes
Class Sarcopterygii
• Order Coelacanthiformes – Family Coelacanthidae (coelecanths)- Fleshy lobed fins- Characteristic osteological features (fig
13.6)- Choanae (internal nostrils)- 2 spp.
Latimeria chalumane (“Old fourlegs”)
• Marjorie Courtenay-Latimer (1939)• J. L. B. Smith
– 2nd specimen (1952)
• Comoro Islands (now Kenia, Madagascar, South Africa…)
• French embargo• Conservation issues• Live observations (nocturnal, 200m)• Ovoviviparous
• Mark Erdmann (1998)• Indonesia (Sulawesi)• Conservation issues• Genetics study• Live observations
Latimeria menadoensis (“King of the Sea”)
Extra Credit: +3% total grade
A Fish Caught in Time : The Search for the Coelacanthby Samantha Weinberg ($10.50 @ www.amazon.com)
Read the book, and write a 1 page essay, clearly expressing YOUR interpretation and opinions of it, as well as how the reading affected your opinion on ichthyology.
Class Sarcopterygii• Infraclass Dipnoi (lungfishes)
– Massive toothplates– Maxillae and Premaxillae bones missing– Functional Lung, choanae (internal nostrils)– Family Ceratodontidae (Australia, 1spp.)– Family Lepidosirenidae (S. America, 1spp.)– Family Protopteridae (Africa, 4 spp.)
LepidosirenidaeS. American lungfishLepidosiren paradoxa
ProtopteridaeAfrican lungfishesProtopterus sp.
Class Sarcopterygii• Infraclass Osteolepimorphi †
– Sister group of modern tetrapods– Similar fins to Devonian Amphibians limbs– Other morphological similarities
Class Actinopterygii
• Order Polypteriformes– Family Polypteridae (bichirs & reedfish)
• 10 spp. (African rivers)• Facultative airbreathers (spiracle exhalation)• Lobed fins, ganoid scales, heterocercal tail,
spiral intestine.• Flagfins (vertical spine with horizontal rays)
Class Actinopterygii
• Order Acipenseriformes (secondary cartilaginous skeleton, heterocercal tail, fin rays, spiral valve intestine). Sturgeons and Paddlefish
– Family Acipenseridae (sturgeons)• 24 spp. (northern hemisphere)• 5 rows bony scutes (modified ganoid scales)• 4 barbels in front of ventral mouth• Fresh water spawning (typically Anadromous)
• Order Acipenseriformes (secondary cartilaginous skeleton, heterocercal tail, fin rays, spiral valve intestine)
– Family Polyodontidae (paddlefishes)• 2 spp. (N. American and Chinese
paddlefishes)• No bony scutes, small scales, ossified
head plates• Freshwater open water plankton feeders• Paddle as electroreceptor?
Class Actinopterygii
Class Actinopterygii
• Order Semionotiformes– Family Lepisosteidae (garfish)
• 7spp. (North and Central America)• Ossified skeleton• Ganoid scales• Slightly heterocercal caudal fin• Backwaters in lakes and rivers, predatory fish• Toxic eggs