Identification Photos: Lumpy Claw Crab, Eriphia squamata: The Lumpy Claw Crab has claws with a unique bumpy structure. The bumps are round to oval in shape. The shell, or carapace, of the Lumpy Claw Crab is mottled and dark green to grey. The legs have black bands.

The shell of the Lumpy Claw Crab varies from 1 to 3 inches in width. The Lumpy Claw Crab is dormant during the day, preying predominately on algae and gastropods, mostly snails, at night.

It has a rather unique eating habit, which has been studied in some detail. In some areas, one claw is larger and stronger than the other, which is attributed to the strength of the snail shells that the crab dines on and must break to eat.

The Lumpy Claw Crab is a highly territorial animal, defending its space by attacking or waving its claws. In Mexican waters, it is found along the coast of all waters of the Sea of Cortez and along the coast of mainland Mexico to Guatemala. It appears to be absent from along the Pacific Coast of the Baja California peninsual and from around the oceanic islands of Mexico.

The Lumpy Claw Crab is one of the most common members of the Xanthidae Family. They are dominant animals found in abundance in rocky, intertidal (between the high and low tide) regions of Mexico's upper Sea of Cortez. They are very hardy, capable of handling severe changes in moisture content and temperatures from freezing to well over 100 degrees.

Lumpy Claw Crab, Eriphia squamata: Collected in March 2006, from a tidal pool at Km. 6 on the East Cape road north of La Playita, Baja California Sur, Mexico. Approximately 2.5 inches in size. Description and photo courtesy of John Snow.