Psittacosauridae
| Psittacosauridae | ||||||||||||
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Skeletal reconstruction of Psittacosaurus |
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| Temporal occurrence | ||||||||||||
| Lower Cretaceous ( Hauterivium to Albium ) | ||||||||||||
| 133.9 to 100.5 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Psittacosauridae | ||||||||||||
| Osborn , 1923 |
The Psittacosauridae are a taxon (a systematic group) of the bird pelvic dinosaur from the group of Ceratopsia . For a long time only the species-rich genus Psittacosaurus was included in this group, but with the little-known Hongshanosaurus , a second genus was described in 2003 .
features
The Psittacosauridae are characterized by the following features: The part of the skull in front of the eye socket is very short, the nasal cavities are high up, the skull window in front of the eye socket is closed, the fourth finger is shortened and consists of only one phalanx (phalange ), and the fifth finger is missing.
Psittacosauridae were rather small (up to 2 meters long), mainly on their hind legs ( biped ) moving dinosaurs. As with all Ceratopsia, there was a rostral bone at the tip of the upper jaw which, together with the predentale in front of the lower jaw, formed the typical “parrot beak”. Like all Ceratopsia, they were herbivores.
All finds of the Psittacosauridae come from the Lower Cretaceous and are around 134 to 100 million years old. All fossils were found in East Asia , mostly China and Mongolia .
Systematics
Apart from the primitive Yinlong , the Psittacosauridae form the sister group of the other Ceratopsia, which are summarized as Neoceratopsia . This is expressed in the following cladogram:
| Ceratopsia |
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The position of Chaoyangsaurus and the closely related Xuanhuaceratops , the Chaoyangsauridae, is controversial . According to You and Dodson (2004), Chaoyangsaurus is an ancient representative of the Neoceratopsia, which was first described by Xuanhuaceratops , Zhou et al. (2006) classify this and Chaoyangsaurus in the family tree as basal Ceratopsia and thus 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) .
- Hailu You, Xing Xu , Xiaolin Wang: A new genus of Psittacosauridae (Dinosauria: Ornithopoda) and the origin and early evolution of marginocephalian dinosaurs. In: Acta Geologica Sinica. English edition. Vol. 77, No. 1, 2003, ISSN 1000-9515 , pp. 15-20, doi : 10.1111 / j.1755-6724.2003.tb00105.x .
Web links
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 , pp. 245-249, online .
- ↑ after Xing Xu, Catherine A. Forster, James M. Clark , Jinyou Mo: A basal ceratopsian with transitional features from the Late Jurassic of northwestern China. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 273, No. 1598, 2006, ISSN 0950-1193 , pp. 1471-2954, doi : 10.1098 / rspb. 2006.3566 .
- ↑ 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 .