Vertebrata Cuvier, 1812 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
   Gnathostomata
     Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
       Subclass Elasmobranchii Bonaparte, 1838 - shark-like fishes see Infraclass Elasmobranchii Bonaparte, 1838
         Superorder Euselachii Hay, 1902 see Subclass Euselachii Hay, 1902
           Order †Ctenacanthiformes Glikman, 1964
             1 Superfamily †Ctenacanthoidea Dean, 1909
             2 Superfamily †Hybodontoidea Owen, 1846 see Order Hybodontiformes Patterson, 1966
             3 Superfamily †Protacrodontoidea Zangerl, 1981 [monotypic] see Order Protacrodontiformes