Alpheidae

Family of crustacean possessing asymmetrical snapping claws

Alpheidae (also known as the snapping shrimp, pistol shrimp, or cracker shrimp) is a family of the shrimp infraorder Caridea that is characterized by having an enlarged and highly modified chelae ("claws") on one leg of their first pair, which is used for various purposes. Around half of the species, such as those in the genus Potamalpheops, lack this trait and have been dubbed "non-snapping shrimp". The family is diverse and worldwide in distribution, consisting of about 1,119 species within 38 or more genera.

From Wikipedia, under CC BY-SA. More on occurri.