Two rare species of Petrolisthes (Decapoda: Anomura: Porcellanidae) from the Ryukyu Islands, with the description of a new species of the genus

Two rarely recorded species, Petrolisthes masakii and P. celebesensis, are redescribed, based on specimens collected from the Ryukyu Islands. Petrolisthes masakii is found with blackish ophiuroids, Ophiocoma erinaceus or O. pica, on dead coral branches around the outer edges of reef flats, and P, celebesensis occurs near the bases of large blocks of dead coral branches in lagoons. A new species, Petrolisthes varicolor; is described from the Ryukyus and Phuket Island. This species closely resembles P.fimbriatus, but differs from the latter in the subparallel branchial margin of the carapace and the coloration of the body, verified by a comparison with syntypes and specimens of P. fimbriatus from Palau and the Philippines.