The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch (or, in chronostratigraphy: the fifth of six stages in the Upper Cretaceous series). The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma (million years ago). It is preceded by the Santonian and it is followed by the Maastrichtian.[1]
Stratigraphic definition
The Santonian was introduced in scientific literature by Henri Coquand in 1857. It is named after the French village of Champagne in the département Charente-Maritime. The original type locality was an outcrop near the village of Aubeterre-sur-Dronne in the same region. Due to changes of the stratigraphic definitions, this section is now part of the Maastrichtian stage.
The base of the Campanian stage is laid at the extinction of crinoid species Marsupites testudinarius. A GSSP had not yet been ratified in 2009. One possible candidate is in a section near a dam at Waxahachie, Texas.
The top of the Campanian is defined as the place in the stratigraphic column were the ammonite Pachydiscus neubergicus first appears.
Subdivision
The Campanian is sometimes subdivided into Lower, Middle and Upper subages. In the Tethys domain, the Campanian encompasses six ammonite biozones. They are, from young to old:
Paleontology
During the Campanian age, a radiation among dinosaur species occurred. In North America, for example, the number of known dinosaur genera rises from 4 at the base of the Campanian to 48 in the upper part. This development is sometimes referred to as the "Campanian Explosion". However, it is not yet clear if the event is artificial, i.e. the low number of genera in the lower Campanian can be caused by a lower preservation chance for fossils in deposits of that age. The generally warm climates and large continental area covered in shallow sea during the Campanian probably favoured the dinosaurs. In the following Maastrichtian stage, the number of North American dinosaur genera found is 30% less than in the upper Campanian.[2]
Animals that lived in the Campanian include:
Ankylosaurs
| Ankylosaurs of the Campanian |
| Taxa |
Presence |
Location |
Description |
Images |
|
Aletopelta
|
|
Point Loma Formation, California, USA |
A medium-sized ankylosaurid, estimated to be around 6 m (20 ft) long |
|
|
Antarctopelta
|
|
Santa Marta Formation, James Ross Island, Antarctica |
A stocky ankylosaur protected by armor plates embedded in the skin. Although a complete skeleton has not been found, the species is estimated to have reached a maximum length of 4 meters (13 ft). Displays characteristics of both ankylosaurids and nodosaurids |
|
Edmontonia
|
Campanian to Maastrichtian |
Horseshoe Canyon Formation, Alberta, Canada |
A bulky nodosaurid at roughly 6.6m (22 ft) long and 2m (6 ft) high. It had small, ridged bony plates on its back and head and many sharp spikes along its back and tail. The four largest spikes jutted out from the shoulders on each side, two of which were split into subspines in some specimens. Its skull had a pear-like shape when viewed from above. |
|
Euoplocephalus
|
|
|
|
Niobrarasaurus
|
|
|
|
|
Nodocephalosaurus
|
|
|
|
|
Panoplosaurus
|
|
Judith River Formation, Alberta, Canada; Montana, USA |
A 5.5-7 m long and 2 m tall nodosaurid |
|
Pinacosaurus
|
|
|
|
|
Saichania
|
|
|
|
|
Shanxia
|
|
|
|
|
Struthiosaurus
|
|
|
|
|
Tarchia
|
|
|
|
|
Tianzhenosaurus
|
|
|
|
Birds
Bony Fish
Cartilaginous Fish
Ceratopsians
Crocodylomorphs
Mammals
Ornithopods
Pachycephalosaurs
| Pachycephalosaurs of the Campanian |
| Taxa |
Presence |
Location |
Description |
Images |
|
Alaskacephale
|
|
Prince Creek Formation, Alaska, USA |
|
|
|
Colepiocephale
|
|
Alberta, Canada |
The oldest known pachycephalosaurid |
|
Goyocephale
|
|
Mongolia |
|
|
Gravitholus
|
|
|
|
|
Hanssuesia
|
|
Alberta, Canada; Montana, USA |
Distinguished from other pachycephalosaurs by having a depressed parietal region, wide frontoparietal dome, broad nasal characteristics, reduced prefontal lobes, and a reduced parietosquamosal shelf. |
|
?Heishansaurus
|
|
|
|
|
Homalocephale
|
|
Mongolia |
Sporting a flat, wedge-shaped skull roof, Homalocephale was different from other pachycephalosaurs. |
|
?Micropachycephalosaurus
|
|
|
|
|
Ornatotholus
|
|
|
|
|
Prenocephale
|
|
|
|
|
Sphaerotholus
|
|
|
|
|
Stegoceras
|
|
|
|
|
Tylocephale
|
|
|
|
|
Wannanosaurus
|
|
|
|
Plesiosaurs
Pterosaurs
Sauropods
Squamates
Testudines
Theropods
References
Notes
- ^ See Gradstein et al. (2004) for a detailed version of the geological timescale
- ^ See Weishampel et al. (2004)
Literature
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
- Weishampel, D.B.; Barrett, P.M.; Coria, R.A.; Le Loueff, J.; Xu, X.; Zhao, X.; Sahni, A.; Gomani, E.M.P. & Noto, C.N.; 2004: Dinosaur distribution, in: Weishampel, D.B.; Dodson, P. & Osmólska, H. (eds.): The Dinosauria, University of California Press, Berkeley (2nd ed.), ISBN 0-520-24209-2, pp 517-606.
External links
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
