Head profile concave at nape. Head shield strongly rugose and granulated; supra-occipital process short, about as long as broad, with median keel, hind end concave. Dorsal and pectoral fins with very strong, thick, and coarsely granulated spine; tip of dorsal spine produced into a long filament; adipose fin rather large. Body with metallic blue luster. Tip of dorsal fin blackish, its filament black; pectoral, pelvic and anal fins dusky; caudal fin paler; adipose fin either entirely black or bearing a large black blotch on upper half.