Entomology > Entomological dictionary > Crustacean

Crustacean

The crustaceans (Crustacea) are a large group of arthropods (55,000 species), usually treated as a subphylum. They include various familiar animals, such as lobsters, crabs, shrimp and barnacles. They are variously found in marine and freshwater, with a few terrestrial members (such as woodlice).

Crustaceans have three distinct body parts: head, thorax, and abdomen (or pleon), although the head and thorax may fuse to form a cephalothorax. They have two pairs of antennae on the head, compound eyes, three pairs of mouthparts and a telson. Smaller crustaceans respire through their body surface by diffusion and larger crustaceans respire with gills. Crustaceans typically have a thick carapace on the dorsal side of their body. Their appendages are typically biramous, including the second pair of antennae (but not the first).


Source: wikipedia, under GFDL


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