Eight specimens of Pseudomonacanthus macrurus (Bleeker, 1857),collected from the southeastern coast of Okinawa Island from October 2006 to February 2008, had the following combination of characters: dorsal fin rays 29-30,anal fin rays 28-29, lower end of gill opening located anterior to anterior margin of orbital, length of caudal peduncle 1.9-2.4 times in head length, caudal fin longer than head length, dorsal profile of head convex above eye, many small brown spots on body, and caudal fin with two vertical brown bands. The species has previously been recorded from the Philippines, Singapore, Indonesia and Papua New Guinea, the present specimens representing the first records from Japan.
