phylum arthopoda clear concept

INSTITIUTE OF MARINE SCIENES &

FISHERIES

UNIVERSITY OF CHITTAGONG

PRESENTATION ON The Phylum:

Arthropoda

PRESENTED BY>> GROUP: A

Tanvir Hosen Monowara mishu

Tanvir Hosen

Monowara Mishu

ARTHROPODA Arthropoda: Arthropoda are triplobastic,

bilaterally symmetrical, metamerically segmented animals with coelom which is reduced and modified. Their body is covered with a thick chitinous exoskeleton which moults periodically and their appendages are jointed and without true nephridia and cilia in their structure.

Example: (i) Penaeus monodon; (ii) Hippa sp

WHY IT IS CALLED ARTHROPODA?

The name arthropods means, “Jointed Legs” and refers to the most characteristics structure of them. It is, therefore the jointed structure of them. The jointed structure of limbs which has earned the name Arthropoda (GK, arthros = jointed; podos = foot) for this phylum.

CHARACTERS:

Arthropod are triplobastic, bilaterally symmetrical, metamerically segmented animals.

Digestive tract is complete, mouth and anus lie at opposite ends of the body.

Circulatory system is open with dorsal heart and arteries but without capillaries.

Fertilization is internal, development is usually indirect through larval stages.

Cilia are entirely absent from all parts of the body.

EXAMPLE Cylops sp. Nebalia sp. Mysis sp. Penaeus monodon Cancer sp. Sqilla sp. Hippa sp. Balanus sp.

SYSTEMATIC POSITION OF P. MONDON: Phylum: Arthropoda Subphylum: Mandibulata Class: Crustacea Sub-class: Malacostraca Order: Decapoda Sub-order: Natantia Section: Penaeidae Genus: Penaeus Species: P. monodon

PENAEUS MONODON

 SYSTEMATIC POSITION OF M. ROSENBERGII:

Phylum: Arthropoda Subphylum: Mandibulata Class: Crustacea Sub-class: Malacostraca Order: Decapoda Sub-order: Natantia Section: Caridae Genus: Palaemon (Macrobrachium) Species: M. rosenbergii

HABIT AND HABITAT OF P. MONODON: Penaeus monodon inhabits marine and

brackish water environment. It is nocturnal creature and lies hidden at the bottom during the day and comes to surface during night in search of food. It walks slowly at the bottom with the help of walking legs and swims actively at the surface with help of swimmerets (pleopods).

FOOD AND FEEDING HABIT OF P. MONODON:

Penaeus monodon is mainly carnivorous, feeding on slow moving miscroscopic animals, small crabs, shrimps, mollusks, marine worms and detritus.

Pascula (1983) started that unlike fishes Penaeus monodon are nibblurs and slow eaters. They take food with their chelae and bring to their mouths and slowly chew on the food pellets. They throw the whole price into mouth if the feed is too small. It is experimental that their feeding activity during low tides, the weak ones (.e.g. just moulted) are attacked by the healthy ones.

CLASSIFICATION

Phylum-Arthropoda

Class:

Crusfacea Merostomata Arachnida Mariapoda Insecta

CLASS-1: CRUSTACEA

Characters: Body is covered externally by a chitinous cuticle. Excretory organs are modified coelomoducts

forming maxillaryor antennary (green) glands. Malpighian tubules are absent.

Digestive tract is almost straight Respiration occurs usually by gills. The crustacean are unisexual. Example: Branchipus Pinaeus monodon

CLASS-2: MEROTOMATA Characters: Aquatic and marine chelicerates, with branchial

respiration. Antennae are absent Excretion by a pair of coxal glands. No

malpighian tubules. Body divisible into two regions, anterior

prosomay cephalothrax and posterior opisthosoma/ abdomen

Prosoma dorsally 2 lateral compound eyes and 2 median simple eyes.

Example: Limulus Eurypterus.

CLASS-3: ARACHNIDA Characters: They are generally small, air-breathing,

mostly terrestrial and solitary arthropods. Which are especially abundant in the warm dry regions.

The great majority are free-living, predaceous or parasitic.

There is no luad. The body is composed of two divisions cephalothrox and abdomen.

The cephalothroax bears simple and sessile eyes and six pairs of jointed limbs comprising one pair of preoral cheliceral. One pair of postoral pedialpi and 4 pairs of walking legs. The antennae and the true jaws are entirely absent the abdomen is usually limbuss but sometimes ends in a telson.

Cuticle is often provided with sensory hair or scales.

Example: Buthus Cryptocellus

CLASS-4: MARIAPODA

Characters: A small group of terrestrial, secretive, air-breathing

arthropods, wholly absent from the sea. Digestive tract simple, straight Sexes separate. Gonad Single but gonoducts paired .

Nervous system not concentrated The eyes are ocelli. Example: Polyxenus geophilus

CLASS-5: INSECTA

Characters: Air breathing mostly terrestrial and aerial and rarely

aquatic arthropods, minute to moderate in size. The body is metamerically segmented, bilaterally

symmetrical and dived into three district regions-lead, thorax and abdomen.

A liver is absent but salivary glands are often present.

The abdomen is distinctly divided into 7-11 segments.

Fertilization is usually internal. Example: Silverfish pulex

LIFE CYCLE OF PENAEUS MONODON:

The following life cycle of Penaeus monodon is typical of other penaeids as well:

Adult P. monodon are bottom dwellers in the offshore areas at depths of 20 to 70 meters. The life cycle starts with the spawning or release of approximately 5,00,000 eggs by a gravid or ripe female. The larvae hatched out 12-15 hrs after spawning, looking very different from the adults. After 10-12 days and two more larval stages. The larvae metamorphose into the post larvae.

  The young post larvae or fry move

shoreward and start appearing in coastal waters around two weeks into their post larval life. They continue migration towards mangrove and other brackish water areas which serve as their nurseries or feeding groups, growing to larger juveniles, post juveniles and sub adults. At this stage P. monodon is mainly carnivorous, feeding on slow moving microscopic animals. Small crabs, shrimps, mollusks, marine worms and detritus.

Although first mating occurs in the estuaries, it is only during or after migration back to the offshore areas that full ripening of the ovaries takes place. First spawning occurs at 10 months of age upon arrival in the offshore areas, followed by 2-3 more consecutive spawning within a single season. The adult remain in the ocean upto a ripe old stage of 3, 4, 5 years unless they die earlier of predation or disease. However, some metapenaeus species reportedly undergo spawning and the larval stage in brackish water areas, completing the life cycle without returning to the open sea.

WRITE A SHORT NOTE ON INK-GLAND?

A pear-shaped ink sac lies over the posterior ventral surface of visceral dome and opens by a duct dorsally into the rectum close to the anus. The terminal part of the duct forms on ejecting ampulla. The ink-gland, lying inside the wall of the large ink-sac, contains a high concentration of melanin pigment and is stored in the ink-sac. When the cuttle fish started, it discharges the ink through the funnel as a black cloud, which forms a sort of smoke screen, under the cover of which the animal escapes from an enemy or approaches a prey.

EXTERNAL MORPHOLOGY OF P.M.:

Shape and size: The body of P. monodon is elongated, more or less spindle shaped and bilaterally symmetrical. The size of the adult is generally 25 to 38 cm in length.

Colouration: Pattern of color is variable. Usually the fresh specimens are dark blue to black. Carapace and abdomen are transversely bended with grey to reddish brown stripes. Pleopods fringed with bright red setae. Pleopods and uropods tipped with light blue color.

PENAEUS MONODON

Rostrum: The rostrum is fixed and rigid, double curved (firstly downward and at the tip slightly upturned). It is armed with 6-8 dorsal and 2-3 ventral teeth but usually the rostral formula is 7/3.

Carapace: The Carapace is smooth and thick. It’s length is 1.5-1.7 times of breadth. The carapace is divisible into various regions. It is armed with spines and marked by grooves (Sulcus) and carina as given below. Carina/Ridge: Castro antennal carina well developed

reaching from antennal to below hepatic spine. Gastro-orbital carina occupies posterior one third of distance between post orbital margin of carapace and hepatic spine; cervical carina well developed, hepatic carina very short and lies horizontally.

Sulcus/ groove: Post orbital groove absent, Gastrofrontal groove present. Gastro-orbital sulcus deep between gastro-orbital carina and post antennal carina. Cervical and hepatic sulcus ill-defined.

Exoskeleton: The entire body and the appendage are covered by a hard and chitinous cuticle, which forms exoskeleton. The exoskeleton is hardened by deposit of salts of lime and colored with various pigments. The hard pieces of exoskeleton are called selerities, which are jointed by softer cuticle forming arthrodial membrane. The cephalothorax consists of a head and thorax. The head is covered with dorsal plate and thorax with a carapace.

DIVISION OF THE BODY: THE BODY OF ADULT PENAEUS MONODON IS CONSISTING OF 19TH APPENDAGES, BEARING SEGMENTS HAVING TWO DISTRICT REGIONS; AN ANTERIOR RIGID CEPHALOTHORAX AND A POSTERIOR MOVABLE ABDOMEN.

Cephalothorax: The cephalothorax is somewhat cylindrical in shape and is uncounted, no external segmentation is marked. It is formed by the union of head comprising five appendages bearing segments and the thorax comprising 8 segments.

Abdomen: The abdomen rounded dorsally but compressed laterally, is jointed, external segmentation is clearly marked and composed of six movable segments having terminal conical piece, telson. The abdomen is often turned downwards. Each segment of the abdomen carries a pair of jointed appendages called pleopods or swimmerets.

Mouth: It is a mid-ventral slit-like aperture lying at the anterior end of the cephalothorax.

Anus: It is longitudinal slit-like aperture lying at the ventral end of the base of telson.

Female genital apertures: These are paired each situated at the inner surface of the coxal of third pair of walking legs.

Male genital aperatues: These are also paired each situated at the inner surface of the coxal of fifth pair of walking leg.

FIGURE: P. MONODON

SEX ORGANS OF P. MONDON?

In P. monodon the following sex-organs are found: Petasma in male Thelycum in female. Petasma: In the fist pair of pleopod of the adult male

of P. monodon, the endopodite modified into an elongated and much folded structure. The two halves of this structure are united along their median margin, forming the male sex organ-petasma. It is symmetrical and reached into the bases of the fourth pereipods consisting of two segments ling dorso-medially clopped together anteriorly by interlocking process and posteriorly lying in close apposition . during copulation, the transfer of spermatophores is done trough petasma.

THELYCUM:THE FEMALE SEX ORGAN IS KNOWN AS THELYCUM,L WHICH IS LOCATED ON THE VENTRAL SURFACE BETWEEN THE BASES OF THE FOURTH AND FIFTH PAIR OF PEREIPODS.

FIG: POSITION OF EXTERNAL MALE REPRODUCTIVE ORGAN OF THE PETASMA OF PP. MONODON.

WRITE DOWN THE LARVAL DEVELOPMENT OF P. MONODON 

Embryo: Viable eggs of P. monodon are spherical, yellowish green in color somewhat translucent ranging from .27 to .31 mm with an average of .29 cm in diameter. The 2-celled, 4-celled morula and embryonic nauplies stages were approximately .5, 1, 1.8 and 11 hours after spawning respectively.

First nauplies: The first nauplies is measured from .30 to .33 mm in total length with .2 mm in body width with an average of .19 mm. There are three pair of appendages:

1st antennareor antennule. 2nd antennae. Mandibles.   The 1st antennae is uniramous, 2nd antenna is

biramous, and the mandible is biramous.

2nd Nauplies: The 2nd nauplies is measured from .37 to .38 mm in total length with an average of .35 mm and from .17 to .22 mm in body width with an average of .19 mm. The major different between 1st and 2nd nauplies is that most of the long setae on each appendages become plumoso.

3rd nauplies: The 3rd nauplies is measured from .36 to .42 mm in total length with an average of .39 mm and from .19 mm to .22 mm in body width with an average of .20 mm. The body become more elongated.

4th nauplies: The nauplies I measured from .34 to .43 mm in total length with an average of .39 mm and from .17 to .20 mm average of .19 mm. The body become cylinder and is elongated posteriorely. A pair of frontal sense organs are present on the anterior margin of the body.

5th nauplies: The fifth nauplies is measured from .39 to .42 mm with an average of and width .19 mm.

6th nauplies: The sixth nauplies is measured from .50 to .58 mm in total length with an average of .54 mm and from .19 to 21 mm width with an average of .20 mm. Furcal development at the posterior end is more pronounced, and a pair of new spine grow inside and outside of the furca resulting in a spine formula of 777.

FIG: 6TH NAUPLIES

1st protozoea: The 1st protozoea measures from .96 to 1.17 mm in total length with an average of 47 and from .47 to .58 mm in CL (Carapace length) with an average of .53 mm and from .42 mm in carapace width with an average of .40 mm.

FIG: 1ST PROTOZOA.

2ND PROTOZOEA: The 2nd protozoea measures from 1.72 to

2.04 mm in total length and from .70 to .77 mm in carapace length with an average of .73 mm. The abdomen is divided into six segments, the telson is not separated from the 6th.

3RD PROTOZOEA: The 3rd protozoea measures from 2.97 to

3.30 mm in total length with an average of 3.12 mm and from 1.14 to 1.21 mm in carapace length with an average of 1.17 mm.

1ST MYSIS: 1st mysis is measured from 3.28 to 4.13 mm in total length and from 1.25 to 1.41 mm in carapace length with an average of 1.31 mm

2ND MYSIS: 2nd mysis is measured from 4.00 to 4.69

mm in total length. The characteristics of this substages from

the 1st are the development of unsemgnted pleopods and spine on the antennal blade.

3RD MYSIS: 3rd mysis is measured from 4.05 to 4.87

mm in total length. The distinguishing characteristics of the 3rd

mysis are the appearance of a dorsal spine (sometimes lacking) on the rostrum and of well developed pleopods.

After the mysis stage they jump into post larval stage.

ECDYSIS AND MOULTING PROCESS OF P. MONODON.

Ecdysis:The process both of ridding the body of old exoskeleton or cuticle and of secreting a new cuticle is called moulting or ecdysis.

Growth and moulting process of Penaeus monodon:The presence of a thick and generally inflexible exoskeleton created problems of growth and locomotion, that had to be overcome in the evaluation of Arthropods. The problem of growth has been eliminated by the phenomenon of moulting which is quite characteristic of the arthropods.

The exoskeleton is made of dead matter and therefore, it can not grow. An the arthropod grows in size with age, the old exoskeleton is shed periodically and a new exoskeleton developed from the underlying hypodermis. Slightly bigger than its predecessor to accommodate the increased body. The process both of riddling the body of old exoskeleton or cuticle and of secreting a new cuticle is called moulting or ecdysis. The ectodermal derivative such as foregut, hindgut and tracheal and some other parts are also shed.

The process is under hormonal control and involves a series of steps as follows:

Just before actual shedding the hypodermal

cells secrete a moulting fluid containing enzymes which completely erodes the endocuticle. Thus the outer hard layer of cuticle becomes loose and free from the underlying hypodermis.

Simultaneously, the three layers of the new soft cuticle are secreted in order beneath the old exoskeleton by the hypodermis.

The old exoskeleton splits longitudinally along the middorsal or lateral sides of the body allowing the animal to pull out of it.

The newly emerged animal rapidly grows in body size by proliferation of cells and absorption of more water. The new cuticle is relatively soft and pliable to enable the animal to stretch and increase in size.

Soon the new cuticle hardens so that further increase in body size cannot occur until the next ecdysis.

The growth stage between two moult is termed an instars. The number of instars during growth period varies of instars during growth period varies with different species. The animal has little protection from enemies while the new cuticle is soft. Frequently the animal goes into hiding until the new cuticle hardness.

Moutlting apparently does more than provide for growth, for fully formed adult crayfishes and lobster continue to moult periodically. It is believed that an additional purpose may be excretion.

 DIGESTIVE SYSTEM OF P. MONODON The digestive system of P. monodon is

composed of alimentary canal and hepatopancreas.

A. Alimentary canal: The alimentary canal consist of foregut, midgut and hindgut. The foregut comprises the mouth, buccal cavity, oesophagus and stomach.

Mouth:The mouth is a large slit-like aperture situated mid-ventrally below the anterior end of head between the third and fourth segments.

Buceal cavity: It is anterior posteriorly compressed and has thick chitinous lining which is thrown into irregular folds.

Oesophagus:The buccal cavity leads into a short but broad oesophagus. Internally the thick muscular wall of the oesophagus is thrown into four prominent longitudinal folds projecting into the lumen of these folds. The anterior is short but the posterior and lateral are longer and more prominent. Each of the lateral folds being subdivided in two smaller unequal folds.

Stomach:The oesophagus leads into a spacious chamber the stomach which occupies most of the cephalothorasic cavity. It is surrounded laterally, ventrally and posteriorly by the hepatopancreas. The stomach is divided into two parts; (a) a large anterior bag-like cardiac stomach and (b) a very small pyloric stomach cardiac and pyloric stomach are separated by a number of valves.

Cardiac stomach:The cardiac stomach is liner internally with delicate cuticle or intima. The inner lining of intima is produced into a very large number inconspicuous longitudinal folds covered by minute bristles.

Pyloric stomach: The pyloric stomach is very small and narrow chamber lying below the posterior end of the cardiac stomach. Its walls are thick and muscular.

Midgut:The midgut is a long, narrow, straight and sunder tube running back along the median line above the mass of the ventral abdominal muscles upto the sixth abdominal segment.

Hindgut: The hindgut extends from the posterior end of the midgut to the anus and forms the shortest portion of the alimentary canal.

Hepatopanereas:The hepatopancreas or the so called liver is a large bilobed, compact, orange coloured grandular mass occupying a considerable area of cephalothoriac cavity. It lies immediately behind the cardiac stomach.

FOOD AND FEEDING MECHANISM OF P. MONODON Penaeus monodon mainly feeds on algae,

moss and other aquatic weeds and occasionally on such small aqautic animals as insects, snails, fish etc. and debris of the bottom. They are more active at dusk and day-break than at any other time. The chelate legs aided by the third maxillepedes, capture and convey the food to the mouth. The coxae of the second maxillepedes hold the food. the incisor processes of mandibles cut it into smaller pieces, which are swallowed with the help of maxillipedes, maxillae and maxilliulae.

Course parts are ejected through the mouth. Inside the buccal cavity, the molar processes of mandibles masticlate the food, which is then conveyed to the cardiac stomach trough the oesophagnes peristaltic action of oesophageal wall and the sucking action of cardiac stomach a the time of feeding, facilitate the passage of food through the oesophagus and the stomach.

DISTINCTIVE CHARACTERS OF CRUSTACEA:

Characters: 1. Essentially aquatic arthropods 2. Size varies from 2.5 mm to 3 meters 3. Body is covered externally by a

chitinous cuticle 4. Body bilaterally symmetrical,

triplobastic and divisible into three regions head, thorax and abdomen.

5. Head bears a larval median eye. 6. Digestive tract is almost straight 7. Respiration occurs usually by gills.

CLASSIFICATION OF CRUSTACEA There are more than 30,000 known species

of crustaceans, grouped in 8 sub-classes as follows:

Sub-class -1: Cephalocaria Most primitive, marine and bottom dwelling Body small, sunder and divided into a

horseshoe – shaped head and a trunk of 19 segments.

Eyes and carapace absent Example: Hutchinnoniella.

Sub-class -2: Branchipoda Characters: Small, primitive, free-living, mostly fresh water

crustaceans.\ Body made of a varying number of body-

segments. Cephalic carapace, when present, is either

bivalved or shield-like.

Order 1. Anostraca (Fairy shrimps) Characters: Carapace absent Eyes stalked Antennae uniramous Example: Branchipus, Eubranchipus,

Oder-2: Notostraca (Tadpole shrimps) Characters: Carapace large and shield-shaped Eyes sessile and close together Antennae reduced or absent in the male . Example: Trips ( = Apus) and lepidurus.

Order -3: Conchostraca (Class Shrimps) Characters: Carapace bivalved. Eyes sessile. Trunk appendages 10 to 32 pairs. Example: Lynceus, Cyzicus.

Sub-class -3: Ostracoda

Body laterally compressed. Body enclosed inbivaled shell. Commonly called seed-shrimps.

Order-1: Myodocopa Found in sea water. Carapace not notched with apertures for

antennae Second antennae used in swimming. Example -: Cypridina, Phylomedes.

Order-2: Platycopa Marine, carapace unnotched . Antennal biramous. Trunk appendages single pair. Example: Cytherella.

Order-3: Podo copa Marine or freshwater, carapace unnotched. Antennae uniramous, clawed at tips. Trunk appendages 2 pairs. Example: Cypris Drawinula.

Order-4: Cladocopa Second antennae biramous. Both pairs of antennae used in swimming. Example: polycope.

Sub-class-4: Mystacocarida Primitive, marine. Body microscopic, elongated, cylindrical. No compound eyes, a nauplies eye present. Example: Derocheilocarus typicus.

Sub-class-5: Copepoda Free swimming, commensal or parasitic. Body small, elongated, composed of ahead. Carapace reduced or absent. Example: Cyclops, Monstrilla.

Order-1: Calanoida Mainly found in freshwater lakes, ponds. Antennae biramous. Example: Calanus,Diaptomus.

Order-2: Harpicticoida

Body construction scarce between segments bearing fourth and fifth legs clearly apparent.

Antennae biramous. Example: Harpacticus.

Order-3: Cyclopoida Found in pond, lakes and also in salt water. Antennae uniramous. Example: Cyclops.

Order_4: Monstrilloida Larvae parasitic in marine polychate worms. Mouth parts and antennae not found. Example: Monstrilla.

Sub-class -6: Branchiura (Fish Liee) Body flat, divided into a head, thorax,

abdomen. One pair of sessile compound eye. Mouth is suctorial. Examples: Argulus (crab liee),

Dolops.

Sub-class -7: Cirripedia ( Barnacles) Body relatively large and imperfectly

segmented Typically 6 pairs of biramous , cirriform.Thoracic

appendages. Abdomen rudimentary , limbuss ,ending in a of

pair caudal styles.

Odrer-1: Thoracica Non-parasitic or commensal, with or without a

stalk. Thoracic appendages 6 pairs. Alimentary canal present. Example: Lepas, Balanus.

Order-2 Acrothoracica Minute, sessile, bore into mollusc shells or

cordals. Naked with reduced mantle. Thoracic appendages less, usually 4 pairs. Example: Trypetesa, Alcippe,

Crytophialus.

Order-3: Ascothoracica Parasitic on echinoderms and corals. Naked with bivalves or reduced mantle. Example: Synagoga, Dendrogaster.

Order-4: Apoda Parasitic in mantle cavity of stalked brancle. Antennae large, biramous and locomotory. Trunk appendages 4 to 6 pairs. Example: Daphnia, Sida.

Sub-class -8: Malacostraca Large-sized crustaceans, marine and fresh

water. Paired compound eyes, stalked or sessile,

present. Antennules often biramous. Example: Nebalia, Mysis.

Order-1: Nebaliacea Primitive marine crustaceans. Stalked eyes. Telson with a pair of caudal style. Example: Nebalia.

Order-2: Mysidacea Marine crustaceans. Carapace covers almost entire thorax. Example: Mysis.

Order-3: Isopoda Body dorso-ventrally flattened. Abdomen is usally short. Example: Oniscus.

Order-4: Decapoda Mostly marine forms. Statocyst present. Example: Astacus.

DIFFERENT BETWEEN PRAWN AND SHRIMP?

Prawn Shrimp

Prawn inhabits in freshwater. Shrimp inhabits in marine water .

Blue in color, occasionally they

are brownish with orange stripes.

Pattern of color is variable

carapace and abdomen are

transversely bended with reddish

brown stripes.

The 2nd abdominal pleuron

overlaps the 1st pleura.

The 2nd abdominal pleuron overlaps only the 3rd pleuron and is itself overlapped by first.

There are 13 teeth in the lower

part of the rostrum.

There are 6-8 dorsal and 2-3

ventral teeth in the rostrum.e.g. Macrobrachium rosenbergii. e.g. Penaeus monodon .

DIFFERENCE BETWEEN PENACIDAE AND CARIDAE?

PenaeidaeCaridea

Pleura of the 2nd abdominal

segment do not overlap those

of the first segment .

Pleura of the 2nd ob abdominal

segment overlap those of the

1st segment.

Third legs usually chelate . Third legs do not chelate.

Carpus of 2nd pair of legs not

annulated.

Carpus of 2nd pair of legs

annulated .

Gills dendrobranchiate . Gills phyllobranchiate .

e.g. Penaeus mondon. e.g. Macrobrachium

rosenbergii.

DIFFERENT BETWEEN MALE AND FEMALE OF P. MONODON

Male P. monodon Female P. monodon

Present petasma on the 1st pair

of pleopods.

Present thelycum on the 4th

and 5th pair of pleopods .

Genital pore on the base of 5th

pleopods.

Genital pore on the base of 3rd

pleopods.

Appendix masculine on the

2nd pair of pleopods.

No appendix masculine.

Smaller than the female. Larger than the male.

Sexual maturity, male 37 mm

in carapace length.

Female 47 mm in carapace

length.

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