Author: Compagno, 1973
Diagnostic Features:
Snout very long and bell-shaped in dorsoventral view, preoral length 1.6 to 1.7 times the mouth width; eyes horizontally oval and dorsolateral, subocular ridges strong; anterior nasal flaps vestigial, formed as small, low, angular points, well separated from each other and mouth; no nasoral grooves; internarial width about 2 times nostril width; mouth very broadly arched and short; labial furrows moderately long, uppers reaching level of upper symphysis; teeth bladelike, compressed, and cuspidate, moderately differentiated in jaws, anteroposteriors with oblique cusps and cusplets, uppers with slenderer cusps and more cusplets than lowetrs; medial teeth well differentiated from anteroposteriors. First dorsal fin very large and sail-like, its base almost equal to length of dorsal caudal margin; its origin over or somewhat anterior to pectoral insertions, and its midbase equidistant between pectoral and pelvic bases or somewhat closer to pectorals; second dorsal smaller than first, about 2/3 as high as first; anal fin considerably smaller than second dorsal; ventral caudal lobe hardly developed in young but short and strong in adults; terminal lobe of caudal fin moderately long and about 3.1 to 3.8 times in dorsal caudal margin.
Remarks:
See Compagno (1973b, 1979) for detailed accounts of the morphology and systematics of this genus.