[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
           Superorder †Cladoselachimorpha
             Order †Symmoriiformes Zangerl, 1981
               Family †Symmoriidae Dean, 1909
                 1 Genus †Symmorium Cope, 1893
                 2 Genus †Stethacanthus Newberry, 1890