[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 †Xenacanthimorpha
             Order †Xenacanthiformes Berg, 1955
               Family †Xenacanthidae Geinitz, 1860
                 1 Genus †Xenacanthus Beyrich, 1848
                 2 Genus †Pleuracanthus Agassiz, 1837, nom. illeg.