This is a commensal crab, living on the highly poisonous Fire Urchin (Asthenosoma varium). It is also referred to as Adam's Urchin Crab and Fire Urchin Crab. They feed on plankton, and grow to a length of about 2cm.
Found singly or in pairs on coral and rocky reefs, living with short spined sea urchins. Widespread in the West Pacific region, at depths of 5 to 15m.
I spotted this critter during a day dive at a depth of about 40 feet. It was a pair of them on a fire urchin. Dive site: Dayang Beach, Talikud Island, Davao.
Lat: 6.95, Long: 125.67
Spotted on Jan 7, 2012
Submitted on Jan 19, 2012
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