Psittacosaurus_mongoliensisYinlong_downsiWannanosaurusGoyocephale_lattimoreiHomalocephaleTylocephale_gilmoreiPrenocephale_prenesPrenocephale_brevisHanssuesia_sternbergiColepiocephale_lambeiStegoceras_validumPachycephalosaurusAlaskacephaleSphaerotholus_goodwiniSphaerotholus_buchholtzaeAcrotholus_audetiStegoceras_novomexicanumAmtocephale_gobiensisOsteologyMaximum ParsimonyBased on reanalysis of the original matrix.Evans_etal_2013a