CERATOPSIA
CLASSIFICATION
Animalia: Vertebrata: Tetrapoda: Sauropsida: Archosauromorpha:
Ornithodira: Dinosauria: Ornithischia
CLADOGRAM:
--Ceratopsia Marsh, 1890 "Ceratops' taxon" == {Ceratops > Pachycephalosaurus} =Ceratopia
| INCERTAE SEDIS:
| unnamed form -- Aptian -- Utah
| indeterminate material (teeth) -- early Cenomanian -- Utah
| unnamed form -- Early Cretaceous -- England
| "Echizensaurus"
| Trachodon
|--Psittacosauria "Psittacosaurus' taxon" == {Psittacosaurus > Ceratops}
| | INCERTAE SEDIS:
| | unnamed form -- middle Barremian -- China
| `--Psittacosaurus
`--Neoceratopsia Sereno, 1986 "new ceratopsians" == {Ceratops > Psittacosaurus}
| INCERTAE SEDIS:
| cf. Leptoceratops (NMV P186385: ulna) -- Albian -- Australia
| indeterminate material -- middle Campanian -- Alberta
| indeterminate material (tooth) -- early Aptian to middle Aptian -- Maryland
| cf. Leptoceratops (dentaries) -- middle-late Campanian -- Alberta
| Asiaceratops
| Magulodon
| Microceratops
| Graciliceratops
| Leptoceratops
| Udanoceratops
|?-Chaoyangsaurus
|--Archaeoceratops
|?-Kulceratops
`---->Coronosauria
ESSAY
| This group of herbivores contains the frilled dinosaurs, including the horned dinosaurs. Like many other groups of Late Cretaceous dinosaurs, they inhabited only Asia and North America. EVOLUTION:Psittacosaurus is the most primitive known ceratopsian. The back of its skull hints at the giant neck frill of later ceratopsians. Its powerful parrot-like beak, for which the genus was named (“parrot lizard”), features an extra bone. This bone, the rostral bone, is unique to ceratopsians. The creatures on this page were all bipedal. From such as these came the quadrupedal coronosaurs. Coronosaurs were generally larger, although at least one bipedal ceratopsian (Udanoceratops) grew to a fairly large size. Bipedal ceratopsians persisted until the end of the Mesozoic, co-existing with the more advanced ceratopsoids. (See Ceratopsinae for a discussion on the “s” in Ceratopsia). |
