Author: Hulley and Penrith, 1966
Diagnostic Features:
Anterior nasal flaps very short, not expanded into barbels; snout moderately long, compressed and conical, length about 2/5 of head length and less than distance from mouth to pectoral origins; gill openings increasing in size from front to back, 5th over twice length of first; lips thick, fringed, but not suctorial; teeth strongly different in upper and lower jaws, uppers small, with narrow, acute, erect cusps and no cusplets, not bladelike, lowers much larger, bladelike, interlocked, with a high, broad, nearly erect cusp and distal blade, edges not serrated; tooth rows 29/34. Both dorsal fins spineless; first dorsal origin well behind free rear tips of pectoral fins, insertion about equidistant between pectoral and pelvic bases and well ahead of pelvic origins; second dorsal fin somewhat larger than first, base less than 1.5 times length of first dorsal base; origin of second dorsal well ahead of pelvic origins; pectoral fins with greatly expanded, broadly lobate free rear tips and inner margins, much as in chimaeras; caudal fin asymmetrical, not paddle-shaped, upper lobe long, lower lobe moderately long subterminal notch well-developed. No precaudal pits or lateral keels on caudal peduncle, but with a midventral keel. Dermal denticles flat and blocklike, not pedicellate, no posterior cusps on flat, depressed crowns. Cloaca greatly expanded and modified as a luminous gland with secretory papillae. Colour blackish brown with conspicuous light fin margins.