Distribution: South Africa to Japan and Australia and New Zealand; Eastern Pacific from California to Galapagos Islands and Peru. Two dorsal fins, each with a spine. Only sharks with dorsal spines and anal fin present. Five pairs of gill slits; eyes without nictitating fold; small spiracles present; nostrils connected with mouth by deep groove. Small species (max 165 cm) with small mouth; anterior teeth small and cuspidate, posterior enlarged and molariform; snout very short and bluntly rounded. Sluggish nocturnal bottom sharks, mainly in shallow waters. Benthos feeder. Oviparous, producing eggs in unique, large, spiral-flanged egg cases. heter- (gr.) = different, odont- (gr.) = tooth
- MASDEA (1997).