Order †Pachycephalosauria Maryañska & Osmólska, 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974
   Family †Pachycephalosauridae Sternberg, 1945
     †Pachycephalosaurini Sullivan, 2003
       Genus †Stenotholus Giffin, Gabriel & Johnson, 1988 see Genus Pachycephalosaurus Brown & Schlaikjer, 1943, nom. cons.
         1 †Stenotholus kohleri Giffin, Gabriel & Johnson, 1987, orth. inval. see Stenotholus kohlerorum Giffin, Gabriel & Johnson, 1987