Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class †Placodermi McCoy, 1848
     Order †Arthrodira Woodward, 1891 see [unranked] Arthrodira Woodward, 1891
       1 Genus †Coccosteus Agassiz, 1844
       2 Genus †Dunkleosteus Lehman, 1956
       3 Genus †Groenlandaspis "Heintz, 1932", nom. illeg. see Genus Gronlandaspis Heintz, 1932