animal order - the order of animals

Marginocephalia, marginocephalian, suborder Marginocephalia - includes bone-headed (pachycephalosaurs) and horned (ceratopsian) dinosaurs

ceratopsian, horned dinosaur - any of several four-footed herbivorous horned dinosaurs with enormous beaked skulls; of the late Cretaceous in North America and Mongolia

Ceratopsidae, family Ceratopsidae - American ceratopsian dinosaurs

genus Protoceratops - small horned dinosaurs

genus Triceratops - genus of herbivorous horned dinosaurs

genus Styracosaurus - genus of horned dinosaurs

genus Psittacosaurus - most primitive genus of horned dinosaurs; early Cretaceous