Squalidae (dogfish sharks) Centrophoridae (gulper sharks) Dalatiidae (sleeper sharks) Echinorhinidae (bramble sharks)
Squaliformes is an order of sharks that includes the smooth dogfish and spiny dogfish and others, about 80 species in four families.
Members of the order have two dorsal fins, no anal fin, and no nictitating membrane. They have five gill slits.
