Body massive, head broadly triangular from above; hump in front of dorsal origin in individuals over 60 mm SL; caudal peduncle very deep, 0.9-1.1 times longer than deep; anterior nostril pierced on front side of a flap; processus dentiformis present; lower lip interrupted medially; a conspicuous hard keel on back between dorsal and caudal fins and along lower edge of caudal peduncle; lateral line complete; anus about 1-2 eye diameters in front of anal-fin origin; 8.5 branched dorsal-fin rays; 5.5 branched anal-fin rays; caudal fin emarginate, with 9+8 branched rays; axillary pelvic lobe present; top of head vermiculated; body with 9-17 bars, much wider than interspaces, of quite regular width but irregularly organized, often fused two by two along dorsal midline, or upper or lower part missing; black bar at caudal-fin base complete, wide, with anterior and posterior projections where it reaches dorsal and ventral midlines; dorsal fin with 2-3 blotches along base; dark marks on fin rays of all fins (Ref. 36949).