†Placodermi McCoy, 1848
   †Arthrodira Woodward, 1891
     †Brachythoraci Gross, 1932
       †Eubrachythoraci Miles, 1971
         †Pachyosteomorphi Stensiö, 1944
           1 ?Family †Brachydeiridae Gross, 1932
           2 ?Family †Leptosteidae Jaekel, 1911
           3 ?Family †Rachiosteidae Stensiö, 1963
           4 Superfamily †Dunkleosteoidea Stensiö, 1963
           5 †Aspinothoracidi Stensiö, 1959
           6 Genus †Kiangyousteus Liu, 1955, incertae sedis [monotypic]