This species is distinguished by the following characters: body moderately deep and compressed, its depth 2.6 to 3 times in standard length (SL) (reported greatest depth of body in subadults at 2.3 in SL, Ref. 90102); dorsal profile of body uniformly convex; adults with a median, broad-based, tapering, horn-like projection extending directly anteriorly from snout at level of lower part of eye to more than 1/2 head length in front of mouth (first developing as a bump on forehead of young of about 10 cm SL; dorsal profile of snout from upper lip to base of horn very short, curved, and nearly vertical; mouth small; teeth small, spatulate, with denticulate edges, about 50 in each jaw; a continuous unnotched D VI,27-29; A II,27-30; pectoral-fin rays 15-17; pelvic fins I,3; caudal fin slightly rounded, without a filament from each corner; 2 bony plates on each side of caudal peduncle, developing moderate keels with age; colour of body olivaceous grey-brown to light grey, usually with vertical dark brown lines on body which break into small spots dorsally and ventrally; some individuals only with small dark spots; head with small dark brown spots or short irregular lines which become long and oblique on horn (dark markings on one pale phase may be faint or absent; in another phase the anterior third of the body may be distinctly paler than the rest); caudal fin whitish with a large diffuse dark blotch centrobasally in fin (Ref. 9808).