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Anomura


Diagnosis

The modern definition of anomurans could be "pseudo-crabs", as the abdomen is not greatly calcified and is almost always reduced and they usually have enlarged chelae on the first pereiopods. Other features used to distinguish anomurans are the fact that the third pereiopods are always achelate and the pleon (while retaining a tailfan) is held beneath the cephalothorax. They include (in order of the images below) the porcelain crabs, squat lobsters and hermit crabs.

Origin

Anomurans are known from the Early Jurassic to the present day.

All images are taken from www.nhm.org/guana/bvi-invt/bvi-surv/deca-inf.htm