Sphaerotholus
| Sphaerotholus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| Upper Cretaceous (late Campanium to Maastrichtian ) | ||||||||||||
| 76.4 to 66 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Sphaerotholus | ||||||||||||
| Williamson & Carr , 2002 |
Sphaerotholus is a controversial genus of bird pelvic dinosaurs (Ornithischia) from the group of Pachycephalosauria .
From sphaerotholus have so far only parts of the skull were found. As with all pachycephalosaurs, the roof of the skull is thickened, the frontal and parietal bones are fused to form the frontoparietal and are strongly arched. For sphaerotholus characteristic is the strong convexity of the skull and certain features in the arrangement of the cranial bones and the bony protuberance at the back. Otherwise nothing is known about these dinosaurs, presumably their physique corresponds to that of the other pachycephalosaurs. As a result, they moved with their hind legs biped and ate primarily on plants.
Two species are known, both of which were found in the United States . The type species is Sphaerotholus goodwini , the remains of which come from the Kirtland Formation in New Mexico . The second species is S. buchholtzae , fossils of which were discovered in the Hell Creek Formation in Montana . The generic name is derived from the Greek words sphaira (= "ball") and tholos (= "dome") and alludes to the vaulted skull roof. All finds come from the Upper Cretaceous , S. goodwini from the late Campanium and S. buchholtzae from the Maastrichtian .
It is disputed whether Sphaerotholus is a valid genus. For example, R. Sullivan sees it as a synonym for Prenocephale . Only further discoveries will clarify this.
literature
- Teresa Maryańska , Ralph E. Chapman, David B. Weishampel : Pachycephalosauria. In: David B. Weishampel, Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 464-477.
- Robert M. Sullivan: A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia). In: Spencer G. Lucas, Robert M. Sullivan (Eds.): Late Cretaceous Vertebrates from the Western Interior (= New Mexico Museum of Natural History and Science. Bulletin. 35, ISSN 1524-4156 ). New Mexico Museum of Natural History and Science, Albuquerque NM 2006, pp. 347–365, digital version (PDF; 4.79 MB) .
Individual evidence
- ^ Dougal Dixon : The World Encyclopedia of Dinosaurs & Prehistoric Creatures. Lorenz, London 2007, ISBN 978-0-7548-1730-7 , p. 359.