Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Class †Placodermi McCoy, 1848
       Order †Arthrodira Woodward, 1891 see Order Arthrodiriformes Grande & Eastman, 1986
         Suborder †Brachythoraci Gross, 1932
           Superfamily †Buchanosteoidea White, 1952
             1 Family †Buchanosteidae White, 1952
             2 ?Family †Williamsaspidae White, 1952