Pachycephalosauridae
Ornithischia Genasauria Cerapoda Marginocephalia Pachycephalosauria Pachycephalosauridae [Herbivore]
Stegoceras, Pachycephalosaurus, their most recent common ancestor and all descendants (Sereno, 1998)
Jurassic Middle
Kyrgyzstan
Ferganocephale adenticulatum - Balabansai Formation
Jurassic Late
Cretaceous Early
England
Yaverlandia bitholus - Wealden Beds, Wessex Formation
Cretaceous Late
Canada
Colepiocephale lambei - [Foremost Formation], Judith River Wedge
Stegoceras lambei - [Foremost Formation], Judith River Wedge
Gravitholus albertae - Judith River Group (Wedge)
Stegoceras - Canada US
Ornatotholus browni - Judith River Group (Wedge)
Stegoceras breve - Judith River Wedge
Stegoceras browni - Judith River Group (Wedge)
Stegoceras edmontonense - Horseshoe Canyon Formation
Stegoceras validum - Judith River Group (Wedge)
Troodon edmontonensis - Horseshoe Canyon Formation
US
Alaskacephale gangloffi - Prince Creek Formation, Alaska
Dracorex hogwartsia - Hell Creek Formation, South Dakota
Hanssuesia sternbergi
Stegoceras sternbergi
Troodon sternbergi
Pachycephalosaurus
Pachycephalosaurus grangeri
Pachycephalosaurus reinheimeri - Judith River Formation, (Wedge)
Pachycephalosaurus wyomingensis - Lance Formation, Hell Creek Formation, Judith River Formation (Wedge)
Troodon wyomingensis - Lance Formation
Tylosteus ornatus - Black Foot Country
Sphaerotholus buchholtzae - Hell Creek Formation
Sphaerotholus goodwini - Kirtland Formation
Stegoceras - Canada US
Stegoceras validum - Judith River Formation (Wedge), Fruitland Formation
Stegoceras edmontonense - Hell Creek Formation
Stegoceras novomexicanum - Fruitland Formation, Kirtland Formation
Stygimoloch spinifer - Hell Creek Formation, Lance Formation
Stenotholus kohleri - Hell Creek Formation
Texacephale langstoni - Aguja Formation, Texas
China
Heishansaurus pachycephalus - Minhe Formation
Troodon bexelli - Minhe Formation
Mongolia
Amtocephale gobiensis - Baynshirenskaya Svita
Prenocephale prenes - Nemegt Formation
Tylocephale gilmorei - Barun Goyot Formation