A Revision of the Pacific Species Of Gall Crabs, Genus Opecarcinus (Crustacea: Cryptochiridae)

Pacific species of the gall crab genus Opecarcinus are reviewed. O. granulatus (Shen), by having a much less ornate carapace and having the cornea situated anterolaterally on the eyestalk, differs from O. crescentus (Edmondson), which has a carapace ornamented with numerous tubercles and the cornea situated terminally on the eyestalk, and is removed from the synonymy of O. crescentus. Five new species are described: O. aurantius, having a very elongate antennular peduncle; O. lobifrons, having the internal orbital angle exceeding the anterolateral angle of the carapace; O. pellops. living specimens having a blue-black cornea; O. pholeter, having 3 longitudinal depressions on the posterior carapace; and O. sierra. having a convex carapace with many larger, subequal, conical tubercles. All of these species were found on agariciid corals. The genus is known from the eastern Indian Ocean, the Pacific Ocean from Asia to Baja California, and from the Atlantic Ocean. A key to all species of the genus is provided.