[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 Euselachii Hay, 1902 - sharks, rays, and related fossils
             Order †Protacrodontiformes [monotypic]
               Family †Protacrodontidae Zangerl, 1981
                 1 Genus †Protacrodus Jaekel, 1925