Squaliformes

Squaliformes is an order of sharks that includes about 97 species in seven families.

Members of the order have two dorsal fins, which usually possess spines, no anal fin or nictitating membrane, and five gill slits. In most other respects, however, they are quite variable in form and size. They are found worldwide, from polar to tropical waters, and from shallow coastal seas to the open ocean.

Classification
Family Centrophoridae Bleeker, 1859 (gulper sharks)
 * Genus Centrophorus
 * Genus Deania

Family Dalatiidae (J. E. Gray, 1851) (kitefin sharks)
 * Genus Euprotomicroides
 * Genus Heteroscymnoides
 * Genus Mollisquama
 * Tribe Dalatiini
 * Genus Dalatias
 * Genus Isistius
 * Tribe Euprotomicrini
 * Genus Euprotomicrus
 * Genus Squaliolus

Family Echinorhinidae Gill, 1862 (bramble sharks)
 * Genus Echinorhinus

Family Etmopteridae Fowler, 1934 (lantern sharks)
 * Genus Aculeola
 * Genus Centroscyllium
 * Genus Etmopterus
 * Genus Miroscyllium
 * Genus Trigonognathus

Family Oxynotidae Gill, 1872 (rough sharks)
 * Genus Oxynotus

Family Somniosidae D. S. Jordan, 1888 (sleeper sharks)
 * Genus Centroscymnus
 * Genus Centroselachus
 * Genus Proscymnodon
 * Genus Scymnodalatias
 * Genus Scymnodon
 * Genus Somniosus
 * Genus Zameus

Family Squalidae Blainville, 1816 (dogfish sharks)
 * Genus Cirrhigaleus
 * Genus Squalus