A new species of the genus Neopetrolisthes Miyake, 1937 (Crustacea: Decapoda: Porcellanidae) from the Ryukyu Islands, southwestern Japan

A new porcellanid crab, Neopetrolisthes spinatus, is described and illustrated based on the specimens collected from Okinawa Island of the Ryukyus, southwestern Japan. This species is well characterized and distinguished from the other species of Neopetrolisthes Miyake by having an uneven dorsal surface of the carapace and supraocular spines. Neopetrolisthes spinatus occurs as a male/female pair on a sea anemone, Heteractis malu (Haddon & Shackleton). Although most of the morphological characters considered to distinguish Neopetrolisthes from Petrolisthes Stimpson are found in some or many species of the latter genus, Neopetrolisthes differs from Petrolisthes by having the gastric region of the carapace strongly elevated.