Superphylum Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
   Phylum Chordata Bateson, 1885 - chordates
     Subphylum Craniata auct.
       Vertebrata Lamarck, 1801 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
         Myopterygii Janvier, 1978 - myopterygians
           Superclass Gnathostomata Gegenbaur, 1874 - jawed vertebrates
             Grade Chondrichthiomorphi see Grade Chondrichthyomorphi
               Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
                 Subclass Elasmobranchii Bonaparte, 1838 - shark-like fishes see Infraclass Elasmobranchii Bonaparte, 1838
                   Infraclass †Xenacanthimorpha see Superorder Xenacanthimorpha
                     Order †Xenacanthiformes Berg, 1955
                       Family †Xenacanthidae Geinitz, 1860
                         1 Genus †Orthacanthus Agassiz, 1843
                         2 Genus †Pleuracanthus Agassiz, 1837, nom. illeg.
                         3 Genus †Triodus Jourdan, 1849
                         4 Genus †Xenacanthus Beyrich, 1848