Class †Placodermi McCoy, 1848
   Order †Arthrodira Woodward, 1891 see [unranked] Arthrodira Woodward, 1891
     †Aspinothoracida see [unranked] Aspinothoracidi Stensiö, 1959
       Genus †Heintzichthys Whitley, 1933
         1 †Heintzichthys gouldii (Newberry, 1885)