Adults are rhomboid in shape, young are rounder (Ref. 7251). Short, stiff, bluntly triangular snout; tail shorter than body (Ref. 5578). Upper surface very rough, with solid thornlets scattered all over disc and tail, underside smooth, except for some prickles on snout; a constant pattern of separate orbital thorns, a regular row of 13-17 large thorns from nape to first dorsal fin (Ref. 3167); large, close-set thorns with star-shaped bases at upper disc (Ref. 5578). Coloration highly variable; brownish grey with scattered irregular black blotches dorsally; white ventrally; with darker spots and blotches on tail and pelvic fins; black spot on tip of tail (Ref. 2708).