Superphylum Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
   Phylum Chordata Bateson, 1885 - chordates
     Subphylum Craniata auct.
       Vertebrata Lamarck, 1801 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
         Myopterygii Janvier, 1978 - myopterygians
           Superclass Gnathostomata Gegenbaur, 1874 - jawed vertebrates
             Grade Chondrichthiomorphi see Grade Chondrichthyomorphi
               Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
                 Subclass Elasmobranchii Bonaparte, 1838 - shark-like fishes see Infraclass Elasmobranchii Bonaparte, 1838
                   Infraclass Euselachii Hay, 1902 - sharks and rays, and related fossils see Subclass Euselachii Hay, 1902
                     Division Neoselachii Compagno, 1977 see Infraclass Elasmobranchii Bonaparte, 1838
                       Subdivision Selachii - sharks see Division Selachii
                         Superorder Squalomorphi
                           Order Squaliformes Compagno, 1973 - dogfish sharks
                             Family Somniosidae Jordan, 1888 - sleeper sharks
                               1 Genus Centroscymnus Barbosa du Bocage & de Brito Capello, 1864 - velvet dogfishes
                               2 Genus Centroselachus Garman, 1913 [monotypic]
                               3 Genus Proscymnodon Fowler, 1934
                               4 Genus Scymnodalatias Garrick, 1956
                               5 Genus Scymnodon Barbosa du Bocage & de Brito Capello, 1864 [monotypic] - velvet dogfishes
                               6 Genus Somniosus Lesueur, 1818
                               6.0 [Genus Rhinoscymnus Gill, 1865] see Subgenus Rhinoscymnus Gill, 1864
                               7 Genus Zameus Jordan & Fowler, 1903