Lumpy Claw Crab

Lumpy Claw Crab, Eriphia squamata

The Lumpy Claw Crab, Eriphia squamata, is one of the most common members of the Xanthidae Family of Brachyuran Crabs, and are known in Mexico as cangrejo moro. They are dominant animals found in abundance in rocky, intertidal (between the high and low tide) regions of the upper Sea of Cortez. They are very hardy, capable of handling severe changes in moisture content and temperatures from freezing to well over 38oC (100oF).  The Lumpy Claw Crab has claws with a unique bumpy structure. The bumps are round to oval in shape. The shell (or carapace) is mottled and dark green to grey. The legs have black bands. The shells widths vary from 2.5 cm (1.0 inch) to 7.5 cm (3.0 inches). The Lumpy Claw Crabs are dormant during the day, preying predominately on algae and gastropods (mostly snails) at night. They have 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 they dine on and must break to eat. They are highly territorial animals, defending their space by attacking or waving their claws. In Mexican waters they are found along the coast of all waters of the Sea of Cortez and along the coast of mainland Mexico to Guatemala; they appear to be absent from along the Pacific Coast of Baja and from around the oceanic islands.

Lumpy Claw Crab, Eriphia squamata. Collected from a tidal pool Km 6 north of Puerto Los Cabos, Baja California Sur, March 2006. Size: 2.5 cm (1.0 inch) x 1.8 cm (0.7 inches).