Crab

The term crab is often applied to several different groups of short (nose to tail) decapods with thick exoskeletons, but only members of the Brachyura are true crabs; other taxa, such as hermit crabs, porcelain crabs, king crabs, and horseshoe crabs are, despite superficial similarities, not crabs at all. Hermit crabs, king crabs and porcelain crabs belong to the Anomala and can be distinguished from true crabs by counting the legs - in Anomala, the last pair of pereiopods (walking legs) is hidden inside the carapace and so only four pairs are visible (counting the claws), whereas uninjured true crabs always have five visible pairs.

External links

• Brachyura entry at ITIS Report
• Brachyura entry at Animal diversity web
• Crab Hunt in Kudat, Sabah, East Malaysia
• Prof. Chuck Holliday's Research Page, Prof. Chuck Holliday, Dept. of Biology, Lafayette College. Contains links to articles on osmoregulation in crabs and other crustaceans.