Order †Pachycephalosauria Maryañska & Osmólska, 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974
   Family †Pachycephalosauridae Sternberg, 1945
     †Pachycephalosaurini Sullivan, 2003
       Genus †[Dracorex] Bakker, R. Sullivan, Porter, P. Larson & Saulsbury, 2006 see Genus Pachycephalosaurus Brown & Schlaikjer, 1943, nom. cons.
         1 †Dracorex hogwartsia Bakker, Sullivan, Porter, Larson & Saulsbury, 2006