A typically marine crustacean with a front pair of legs specialized as pincers (chelipeds) and used for food capture, signalling, and fighting; usually walks sideways, using four pairs of walking legs; also capable of swimming; body broad, flattened, with a hard outer covering (carapace); abdomen permanently tucked up beneath body; eyes usually movable on stalks; some species terrestrial, some found in fresh water; eggs carried by females, usually hatching into a planktonic larval stage (zoea); many species exploited commercially for food. (Class: Malacostraca. Order: Decapoda.)
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Callinectes sapidus |
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Dromiacea Homolodromioidea Dromioidea Homoloidea Eubrachyura Raninoidea Cyclodorippoidea Dorippoidea Calappoidea Leucosioidea Majoidea Hymenosomatoidea Parthenopoidea Retroplumoidea
Cancroidea Portunoidea Bythograeoidea Xanthoidea Bellioidea Potamoidea Pseudothelphusoidea Gecarcinucoidea Cryptochiroidea Pinnotheroidea * Ocypodoidea * Grapsoidea *
An asterisk (*) marks the crabs included in the clade Thoracotremata. Crabs vary in size from the pea crab, only a few millimetres wide, to the Japanese spider crab, with a leg span of up to 4 m . Diet
Crabs are omnivores, feeding primarily on algae , and taking any other food, including molluscs, worms, other crustaceans, fungi, bacteria and detritus, depending on their
availability and the crab species. Other important taxa include Portunus pelagicus, several species in the genus Chionoecetes, the blue crab (Callinectes sapidus),
Charybdis spp., Cancer pagurus, the Dungeness crab (Cancer magister) and Scylla serrata, each of which provides more than 20,000 tonnes
annually . Evolution and classificationThe infraclass Brachyura contains about 70 families, as many as the remainder of the Decapoda . Gallery
Similar animalsSeveral other groups of animals are either called crabs or have the term "crab" in their names. These include hermit crabs, porcelain crabs and king crabs, which, despite superficial similarities to true crabs, belong to the Anomura. |
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