Order †Pachycephalosauria Maryañska & Osmólska, 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974 Family †Pachycephalosauridae Sternberg, 1945 †Pachycephalosaurini Sullivan, 2003 Genus †"Troödon" Leidy, 1856 see Genus Troodon Leidy, 1856, nom. dub. †Troödon bexelli Bohlin, 1953 see Troodon bexelli Bohlin, 1953