A large and diverse group of sharks with two dorsal fins, usually commencing with a spine, the first dorsal fin originating well before the pelvic fins; 5 gill slits, spiracles, and skin densely covered in denticles. All species lack an anal fin.
The Order comprises more than 130 species in seven families, and includes the very small pygmy sharks of the genus Squaliolus, and large sleeper sharks that grow to more lengths of more than 6 metres.
Dogfish sharks live in coastal and deepwater habitats, and some species are bioluminescent. Representatives of all families are found in Australian waters.
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Straube N, Li C, Julien M. Claes JM, Corrigan S, Naylor GJP. (2015) Molecular phylogeny of Squaliformes and first occurrence of bioluminescence in sharks. BMC Evolutionary Biology (2015) 15: 162 DOI 10.1186/s12862-015-0446-6