(THYREOPHORA,(ORNITHOPODA,((Stenopelix,(Goyocephale,(Homalocephale,(Stegoceras,((Tylocephale,Prenocephale),(Stygimoloch,Pachycephalosaurus)))))),(Psittacosaurus,(Chaoyangsaurus,(Archaeoceratops,(Leptoceratops,(PROTOCERATOPSIDAE,(Montanoceratops,(Turanoceratops,(CENTROSAURINAE,CERATOPSINAE)))))))))));