Ornatotholus
| Ornatotholus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| Upper Cretaceous (late Campanium ) | ||||||||||||
| 76.4 to 72 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ornatotholus | ||||||||||||
| Galton & Sues, 1983 |
Ornatotholus is a controversial genus of the bird pelvic dinosaur (Ornithischia) from the group of the Pachycephalosauria . The only species described is O. browni .
So far only the top of the skull of Ornatotholus has been found. As with all pachycephalosaurs, this is composed of the frontal bone and the parietal bone and has the thickening typical of this group of dinosaurs. The roof of the skull is relatively flat and has an open fenestra supratemporalis (the upper skull window in the temporal region ).
Fossil remains of this dinosaur were in the Dinosaur Park Formation in Alberta ( Canada found) and first described the 1979th Initially, the finds were incorporated into the genus Stegoceras , described in 1983 as a separate genus Ornatotholus .
The type species and the only species described is O. browni . The find is dated in the Upper Cretaceous (late Campanium ) to an age of about 76 to 72 million years.
Whether Ornatotholus is a valid genus is disputed. R. Sullivan regards the finds only as juveniles of Stegoceras and assigns them to this genus; Teresa Maryańska et al., However, list them as an independent genus and place them in a cladistic study as a relatively primitive pachycephalosaur due to the open skull window. 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. 356.