Order †Pachycephalosauria Maryañska & Osmólska, 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974 Family †Pachycephalosauridae Sternberg, 1945 ?Genus †[Wannanosaurus] Hou, 1977 1 †Wannanosaurus yansiensis Hou, 1977