Author: Compagno, 1973
Diagnostic Features:
Trunk cylindrical or slightly compressed, not depressed and raylike. Head conical and slightly elevated, not depressed and laterally expanded; 5 pairs of gill slits present on sides of head, the last three above the pectoral fin bases; spiracles present and small, behind and below the eyes; nostrils without barbels but with strong nasoral grooves and circumnarial grooves, connected to mouth, with anterior nasal flaps elongated posteriorly and reaching mouth; eyes on dorsolateral surface of head, without nictitating lower eyelids; snout very short and bluntly rounded, not sawlike and without rostral barbels; mouth moderate, arched and short, well in front of eyes; labial furrows very large, present on both jaws; teeth strongly differentiated along jaws, with anterior teeth small and cuspidate and posteriors enlarged, acuspidate and molariform; no small intermediate teeth or a gap between anterior and lateroposterior teeth in upper jaw. Two dorsal fins, each with a stout fin spine, the first with its origin over the pectoral bases or inner margins; pectoral fins moderately large, not raylike and without triangular anterior lobes; pelvic fins moderately large, with vent continuous with their inner margins; anal fin present; caudal fin with a moderately long dorsal lobe and moderately long ventral lobe, the latter shorter than the dorsal lobe. Vertebral axis raised into the dorsal caudal lobe; intestinal valve of spiral type.