Dorsal-fin rays IX, 4-25 ; anal-fin rays III, 3-24 ; pectoral-fin rays 16. Body brown with a black bar on upper edge of gill opening; head spotted; a less intense dark mark just behind the eye, connected narrowly with the dark bar. Around caudal peduncle spine with a dark brown region; outer third of upper pectoral rays pale yellow. Large adults develop a distinctly convex head profile.
habitats
Generally found in coastal to outer reef flats from 1 to at least 30m. Usually in schools of mixed similar species when grazing algae.
Distribution
Indo-West Pacific: From the Andaman Sea and Christmas Island in the eastern Indian Ocean to the Philippines and the Line Islands, north to the Ryukyu Islands, south to Samoa.
Taiwan: South, Hsiaoliuchiu, Lanyu, Lyudao, North.
沈世傑 編 Shih-Chieh Shen ed. 1993 
