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 †Osteostracomorphi [monotypic]
             Class †Cephalaspidomorphi Kiaer & Stensiö, 1920 see Class Osteostraci Lankester, 1868
               Order †Cephalaspidiformes Halstead Tarlo, 1967
                 †Cornuata
                   1 Family †Benneviaspidae Denison, 1951 see Family Benneviaspididae Denison, 1951, nom. praeval.
                   2 Family †Cephalaspidae Agassiz, 1844 see Family Cephalaspididae Agassiz, 1844, nom. praeval.
                   3 Family †Dartmuthiidae Robertson, 1935 see Family Tremataspididae Woodward, 1891, nom. praeval.
                   4 Family †Kiaeraspidae Stensiö, 1932 see Family Kiaeraspididae Stensiö, 1932, nom. praeval.
                   5 Family †Sclerodidae Berg, 1940, orth. inval. see Family Sclerodontidae Berg, 1940
                   6 Family †Thyestiidae nom. imperf. see Family Thyestidae Rohon, 1892
                   7 Family †Tremataspidae Woodward, 1891 see Family Tremataspididae Woodward, 1891, nom. praeval.
                   8 Family †Zenaspidae Nelson, 2006, nom. illeg. see Family Zenaspididae Stensiö, 1958