Order †Pachycephalosauria Maryañska & Osmólska, 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974 Family †Pachycephalosauridae Sternberg, 1945 †Pachycephalosaurini Sullivan, 2003 Genus †[Stygimoloch] Galton & Sues, 1983 †Stygimoloch spinifer Galton & Sues, 1983