THYREOPHORA

ORNITHOPODA

Stenopelix

Goyocephale

Homalocephale

Stegoceras

Pachycephalosaurus

Stygimoloch

Prenocephale

Tylocephale

Psittacosaurus

Chaoyangsaurus

Archaeoceratops

Leptoceratops

PROTOCERATOPSIDAE

Montanoceratops

Turanoceratops

CERATOPSINAE

CENTROSAURINAE