CORONOSAURIA
CLASSIFICATION
Animalia: Vertebrata: Tetrapoda: Sauropsida: Archosauromorpha:
Ornithodira: Dinosauria: Ornithischia: Ceratopsia
CLADOGRAM:
--Coronosauria "crowned lizards" == {Triceratops + Protoceratops}
|--Bagaceratops
|--Breviceratops
|--Protoceratops
`--Ceratopsoidea == {Ceratops + Montanoceratops} =Ceratopoidea
|--Montanoceratops
`--Ceratopsomorpha "Ceratops forms" == {Ceratops + Zuniceratops}
|--Zuniceratops
`--+--Turanoceratops
`--Ceratopsidae == {Ceratops + Centrosaurus} =Agathaumidae =Ceratopidae
| INCERTAE SEDIS:
| Agathaumas
| Claorhynchus
| Dysganus
|---->Centrosaurinae
`---->Ceratopsinae
[ Top | Classification | Essay ]ALTERNATE CLADOGRAM:
--Coronosauria
|--Ceratopsoidea
`--Protoceratopsidae == {Protoceratops > Ceratops}
|--Bagaceratops
|--Breviceratops
`--Protoceratops
[ Top | Classification | Essay ]ALTERNATE CLADOGRAM:
--Ceratopsidae =Ceratopsoidea =Ceratopsomorpha
|--Centrosaurinae
| |--Montanoceratops
| `--+ (other centrosaurines)
`--Ceratopsinae
|--Zuniceratops
`--+ (other ceratopsines)
[ Top | Classification | Essay ]ALTERNATE CLADOGRAM:
--Ceratopsoidea
|--Ceratopsomorpha
`--Leptoceratopsidae =Leptoceratopidae
|--Leptoceratops
`--Montanoceratops
[ Top | Classification | Essay ]ALTERNATE CLADOGRAM:
--+ == {Avaceratops + Chasmosaurus + Centrosaurus} =Ceratopsidae sensu Penkalski & Dodson, 1999
|--Avaceratops
`--Ceratopsidae
ESSAY
| CHARACTERISTICS:This group includes all of the quadrupedal ceratopsians. Coronosaurs tend to be larger and have larger neck frills than more primitive ceratopsians. There has been much dispute as to whether the front limbs of coronosaurs were held fully erect or sprawling to various degrees. An intermediate posture seems most likely. The most primitive coronosaurs, like the well-known Protoceratops, lacked horns, although they bore small bumps on their noses. Montanoceratops, the most primitive known ceratopsoid, possessed a true horn on its nose. In addition to the nasal horn ceratopsomorphs like Zuniceratops possessed brow horns above their eyes. The function of the neck frills in these and other ceratopsians is not certain. They may have borne colorful displays, protected the neck from predators, anchored powerful cheek muscles, amplified low-frequency sounds, or performed a combination of these functions. In Protoceratops, one gender (male?) has a much wider frill than the other, supporting the idea that these were used as sexual displays. T HE M IGHTY CERATOPSIDS:Hailing from the very latest stretch of the Mesozoic Era, ceratopsids were the pinnacle of ceratopsian evolution. They included some of the very largest ornithischians, such as the mighty Triceratops. They are only known from North America (unless the Asian Turanoceratops is really a ceratopsid). Skin impressions are known from both centrosaurine ceratopsids (Centrosaurus) and ceratopsine ceratopsids (Chasmosaurus). They both show large, flat scales interspersed with larger, round tubercles. CLASSIFICATION:The genera listed here, plus other neoceratopsians were once grouped in the family Protoceratopsidae (=Protoceratopidae), since they all had claws instead of hooves. Most now consider this a paraphyletic (and hence invalid) grouping. There may, however, be a monophyletic (hence valid) group of basal coronosaurs which would be termed Protoceratopsidae. |
