CLASSIFICATION OF CARCINUS (CRAB)​

KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)

PHYLUM :- ARTHROPODA (Jointed appendages.)

SUB-PHYLUM:- CRUSTACEA (Exoskeleton thick, antennae 2 pairs, jaws 3 pairs.)

CLASS :- MALACOSTRACA (Free-living Crustacea with compound eyes, biramous antennules, mandibles, 8 thoracic and 6 abdominal segments having appendages.)

ORDER :- DECAPODA (Carapace present; first three thoracic limbs from maxillipedes.)

FAMILY :- PROTUNIDAE (Flattening of the fifth pair of legs into broad paddles)

GENUS :-  Carcinus (The common crab)

GEOGRAPHICAL DISTRIBUTION

  • It has cosmopolitan distribution and specially found in Europe, U.S.A. and India.

HABIT AND HABITAT

  • Carcinus is found buried among rocks or mud in shallow water. The crabs are highly specialized crustacean. Breeding season is spring.feeds on a variety of molluscs, worms, and small crustaceans, potentially impacting a number of fisheries.

CARCINUS (CRAB)​ DIAGRAM, ARTHROPODA

GENERAL CHARACTERSTICS OF CARCINUS (CRAB)​

  • Commonly called as Rock crab or True crab.
  • Body generally dorsoventrally compressed and consist of a large and broad cephalothorax and a stumpy abdomen.
  • Cephalothorax is broader than long.
  • The carapace is fused with epistome at the sides and nearly always in the middle.
  • Rostrum absent.
  • Small antennules, antennae and eye spots are contained in the sockets of the carapace.
  • Third maxillipedes are broad flat, valve like covering the other mouth parts on ventral surfaces.
  • Five pairs of thoracic legs are well developed.
  • Abdomen is reduced and fixed under cephalothorax. It is permanently bent under the cephalothorax fitting into a groove in the thoracic sterna, thus remaining invisible in the dorsal view of the animal. 
  • Abdomen is narrower in male but somewhat broader in female. The abdominal pleura greatly reduced or absent and the abdomen without tailfans.
  • Pleopods are greatly reduced. The male has only 2 pairs of pleopods to act as copulatory organ while the female has 4 pairs for the attachment of the eggs. Uropods are absent. 
  • Females can produce up to 185,000 eggs, and larvae develop offshore in several stages before their final moult to juvenile crabs in the intertidal zone
  • Young hatches in the zoaea stage and passes through a megalopa stage before reaching maturity.
CARCINUS (CRAB)​ DIAGRAM, ARTHROPODA

IDENTIFICATION

  • The animal contains stumpy abdomen and all above characters, hence it is Carcinus.

CARCINUS (CRAB)​ DIAGRAM, ARTHROPODA
CARCINUS (CRAB)​ DIAGRAM, ARTHROPODA
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