The Knifetooth dogfish, Scymnodon ringens, is a harmless sleeper shark of the family Dalatiidae, found in the eastern Atlantic, from Scotland to Spain, Portugal, and Senegal, and the southwest Pacific from New Zealand, between latitudes 58Â° N and 15Â° N, at depths of between (200 and 1,600 m). Its length is up to 3.61 ft (1.1 m).
The Knifetooth dogfish is a rare species inhabiting continental slopes, usually mesopelagic although taken most often near the bottom. It is black in color, with small dorsal fin spines, and a short snout. There are small lanceolate teeth without cusplets in the upper jaw and huge high, knife-cusped cutting teeth in the lower jaw; its razor-edged lower teeth are used to attack and dismember large prey. The mouth is very wide and broadly arched, and the caudal fin has a weak subterminal notch and no lower lobe.
Its flesh is utilized dried salted for human consumption and for fishmeal.
Reproduction is ovoviviparous.