| Distribution |
Antarctic to Arctic, Northern and Southern Hemisperes, coastal and oceanic. Includes four subfamilies (Etmopterinae, Somniosinae, Oxynotinae, and Dalatiinae). Except in Etmopterinae , most members without spines in dorsal fin; luminous organs present (except in Somniosus pacificus), appearing as black dots mainly on ventral surface. Etmopterinae has grooved spines in both dorsal fins, caudal fin with subterminal notch. Oxynotinae has very high, and compressed body, triangular in cross section; dorsal fins very high, each with a spine. The subfamilies are sometimes separated as independent families by various authors: Oxynotidae; Somniosidae (dorsal fins without spines, first dorsal fin originating in front of pelvic fins but much closer to pectoral fins) and Etmopteridae (dorsal fin with spines, teeth with prominent central cusp flanked by one or two smaller cusplets) . Dalatiidae has dorsal fins without spines, first dorsal fin originating in front of pelvic fins but much closer to pelvic fins |
Vipe Dogfish 