Family: SOMNIOSIDAE, Shark-sleeper, Sleeper Sharks, Sleeper Shark

SOMNIOSIDAE

SLEEPER SHARKS

A family of small to very large sharks; body cylindrical to slightly compressed; eyes on side of head, without nictitating membranes;  spiracles large, just behind eyes; snout variable in shape, without barbels; mouth short, nearly transverse; top teeth narrow, needle-like, without cusplets, non overlapping; bottom teeth blade-like, overlapping, without cusps, notched on rear edge; gill slits 5, all before pectoral fin; 2 dorsal fins, with or without spines, any spines grooved, small, on both fins; 1st dorsal variable  in size, larger than to small than 2nd dorsal; origin of 1st dorsal about over pectoral free rear tips; no anal fin; pelvic fins ~equal to or larger than 2nd dorsal; tail fin strongly asymmetrical, upper lobe with notch under tip, lower lobe strong to absent; usually no keels or pits before base of tail fin; skin denticles close-set, not enlarged.

The family has 7 genera and 17 species; ranges from the tropics to the arctic zones; 5 species in 3 genera in our area.