Lumpy Claw Crab, Eriphia squamata
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).
General information: The Lumpy Claw Crab, Eriphia squamata (Stimpson, 1859), is one of the most common members of the Xanthidae Family of Brachyuran Crabs, and are known in Mexico as Cangrejo Moro. They are highly territorial animals, defending their space by attacking or waving their claws. They are nocturnal creatures hiding in crevices during the day and coming out at night to feed.
Identification: 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). They have highly tuberculate chelae being large and round to oval shaped. The Lumpy Claw Crab can be easily confused with the American Pebble Crab, Daira americana (tan color with purple tinges around the eyes and mouth; numerous lumps on the carapace).
Habitat and Range: The Lumpy Claw Crab 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 is found in all Mexican waters of the Pacific Ocean with the exception that they are absent from the west coast of the Baja Peninsula. They can range as far south as Ecuador and the Galapagos islands.
Diet: The Lumpy Claw Crabs are nocturnal predator’s preying predominately on algae and gastropods (mostly snails). 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.
Conservation Status: The Lumpy Claw Crab has not been formally evaluated from a conservation status. However, they are common and of limited interest to most and should be considered to be of Least Concern.