[Phylum] Chordata Bateson, 1885 - chordates
   Subphylum Craniata auct.
     Infraphylum Vertebrata Lamarck, 1801 - vertebrates
       Superclass Gnathostomata Gegenbaur, 1874 - jawed vertebrates
         Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
           Subclass Holocephali Bonaparte, 1832
             Order †Eugeneodontiformes Zangerl, 1981
               Suborder †Edestoidei
                 1 Family †Helicoprionidae Karpinsky, 1911
                 2 Family †Edestidae Leidy, 1857