Chordata Bateson, 1885 - chordates
   Class Elasmobranchii Bonaparte, 1838 see Infraclass Elasmobranchii Bonaparte, 1838
     Subclass Selachii see Division Selachii
       Order Tectospondyli
         Suborder Squaloidei Müller & Henle, 1838 see Order Squaliformes Compagno, 1973
           67 Family Squalidae Blainville, 1816 - dogfish sharks
           68 Family Oxynotidae Gill, 1863 - rough sharks
           69 Family Scymnorhinidae see Family Dalatiidae Gray, 1851
           70 Family Somniosidae Jordan, 1888 - sleeper sharks