[Phylum] Chordata Bateson, 1885 - chordates
   Subphylum Craniata auct.
     Infraphylum Vertebrata Lamarck, 1801 - vertebrates
       Superclass Gnathostomata Gegenbaur, 1874 - jawed vertebrates
         Class †Placodermi McCoy, 1848
           †Arthrodira Woodward, 1891
             Order †Phlyctaeniiformes
               Suborder †Brachythoraci Gross, 1932
                 †Coccosteomorphi Stensiö, 1944 - coccosteomorphs
                   Family †Mylostomatidae Woodward, 1891
                     1 Genus †Mylostoma Newberry, 1883
                     2 Genus †Trachosteus Newberry, 1890
                     3 Genus †Kendrickichthys Dennis & Miles, 1980