It has curved and pointed carapace that reaches only 1.3cm in width. It is dark-brown and the front side has a white or pale-yellow margin. There are also two longitudinal lines of the same pale color on its back.
E. pentagonus is a species of crab in the family Pilumnidae found from the Red Sea and East Africa to French Polynesia and the Hawaiian Islands. This crab is a parasite that lives in the rectum of the double-spined sea urchin (Echinothrix calamaris).
Spotted this tiny critter on a double-spined urchin during a night dive at Dayang Beach. It was at a depth of about 12m.
Lat: 6.95, Long: 125.67
Spotted on Jul 26, 2012
Submitted on Aug 1, 2012