Chaoyangsaurus
| Chaoyangsaurus | ||||||||||||
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Reconstruction of Chaoyangsaurus |
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| Temporal occurrence | ||||||||||||
| Upper Jurassic ( Tithonian ) | ||||||||||||
| 152.1 to 145 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Chaoyangsaurus | ||||||||||||
| Zhao, Cheng & Xu , 1999 | ||||||||||||
| Art | ||||||||||||
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Chaoyangsaurus is a genus of pelvic dinosaurs (Ornithischia) from the group of Ceratopsia . He is one of the older and more primitive representatives of this group.
features
From chaoyangsaurus only parts of are far skull and scattered bones of the body skeleton known. It was a small dinosaur, probably 1 to 2 meters long. The rostral bone (at the tip of the upper jaw) and the wide spreading cheek region show that it belongs to the Ceratopsia. Some features resembled those of Psittacosaurus , which Chaoyangsaurus presumably resembled. Differences to this genus lie in the larger head, a keel-shaped predentale (the foremost bone of the lower jaw) and in the teeth of the intermaxillary bone (premaxillary), which were straight and approximately cylindrical. The teeth of the upper jaw were chisel-shaped, like all ceratopsia, Chaoyangsaurus was herbivorous.
Discovery and dating
The Chaoyangsaurus fossil remains were discovered in the Tuchengzi Formation in Liaoning Province , China . Even before it was first described, this dinosaur was mentioned in various works since the early 1980s, under the names Chaoyoungosaurus and Chaoyangosaurus , which are now considered invalid nomina nuda . The first formal description was given by Zhao Xijin et al. in 1999. The generic name is derived from the city of Chaoyang . The type and only known species is C. youngi , the specific epithet honors the well-known Chinese paleontologist CC Young . The finds in the Upper Jurassic ( Tithonian ) are dated to an age of around 152 to 145 million years, but could possibly also come from the earliest Cretaceous .
Systematics
Chaoyangsaurus is classified together with the Xuanhuaceratops described in 2006 and the Hualianceratops described in 2015 in the family Chaoyangsauridae, which are counted among the basic representatives of the Ceratopsia . The exact systematic position within this group of dinosaurs is controversial. You & Dodson (2004) see Chaoyangsaurus as the most basic representative of the Neoceratopsia and thus more highly developed than the Psittacosauridae . Zhao et al. (2006), on the other hand, the first to describe Xuanhuaceratops , consider this and Chaoyangsaurus to be more primitive than the Psittacosauridae.
literature
- You Hailu, Peter Dodson : Basal Ceratopsia. 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. 478-493, digitized version (PDF; 807.25 kB) .
- David E. Fastovsky , David B. Weishampel: The Evolution and Extinction of the Dinosaurs. 2nd edition. Cambridge University Press, Cambridge et al. 2005, ISBN 0-521-81172-4 .
- Xijin Zhao , Zhengwu Cheng, Xing Xu , Peter J. Makovicky : A New Ceratopsian from the Upper Jurassic Houcheng Formation of Hebei, China. In: Acta Geologica Sinica. English edition. Vol. 80, No. 4, 2006, ISSN 1000-9515 , pp. 467-473, doi : 10.1111 / j.1755-6724.2006.tb00265.x .
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 245, online ( memento of the original of July 13, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ Fenglu Han, Catherine A. Forster, James M. Clark and Xing Xu. 2015. A New Taxon of Basal Ceratopsian from China and the Early Evolution of Ceratopsia. PLoS ONE. DOI: 10.1371 / journal.pone.0143369
