Parthenopidae MacLeay, 1838

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 226

Family Parthenopidae MacLeay, 1838

Members of the family Parthenopidae commonly are called elbow crabs. The elongate chelipeds, folded across the front, suggest the name. These sand-dwelling crabs, mostly tropical in distribution, are represented in California by only one species.

Parthenopid crabs have retractile eyes with small and well-defined orbits. The basal antennal segment is small and deeply imbedded between the inner angle of the orbit and the pits at the bases of the first antennae. The first antennae fold somewhat obliquely, not vertically. The distinctive chelipeds have fingers bent at an angle. Pereopods 2–5 are short, flattened and have broad segments.

Elbow crabs can dig into sand and remain motionless with only the eye, apex of the rostrum and a respiratory passage exposed. Their cryptic coloration renders them further difficult to detect.