Superphylum Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
   Phylum Chordata Bateson, 1885 - chordates
     Subphylum Craniata auct.
       Infraphylum Vertebrata Lamarck, 1801 - vertebrates
         Superclass Gnathostomata Gegenbaur, 1874 - jawed vertebrates
           Eugnathostomata
             Grade Chondrichthyomorphi [monotypic]
               Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
                 Subclass Holocephali Bonaparte, 1832
                   [stem] Order †Petalodontiformes Zangerl, 1981
                     1 Family †Janassidae Jaekel, 1898
                     2 Family †Pristodontidae Woodward, 1889
                     3 Family †Belantseidae Lund, 1989
                     4 Family †Petalodontidae Newberry & Worthen, 1866