Sinornithoides
| Sinornithoides | ||||||||||||
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Live reconstruction of Sinornithoides youngi |
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| Temporal occurrence | ||||||||||||
| Lower Cretaceous (late Barremian to early Aptian ) | ||||||||||||
| 129.4 to 123 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Sinornithoides | ||||||||||||
| Russell & Dong , 1994 | ||||||||||||
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Sinornithoides ("Chinese bird-like") is a genus of very small theropod dinosaur from the Lower Cretaceous of Central Asia .
Fossils of this Troodontid were discovered in deposits from the late Lower Cretaceous (late Barremian to early Aptian ). With a length of about one meter, it is one of the smallest known theropods . Sinornithoides lived in what is now China and presumably ate invertebrates and other small prey.
features
With a body length of 1.1 meters, the weight of the sinornithoid was estimated to be around 2.5 kilograms . The skull shows many features ( synapomorphies ) in common with other troodontids : For example, it is laterally deepened, and the brain skull has a bulla (a bubble-like elevation) (parabolic phenoid). Sinornithoides can be distinguished from related species by some skull features, although the first description could not describe any autapomorphies (unique features), since other troodontids are often too incomplete. Sinornithoides differs from Saurornithoides in that it has a proportionally shorter skull and from Troodon in that the eye sockets are more on the side of the skull .
Description history
The type species Sinornithoides youngi was first described scientifically in 1994 by Dale Russell and Dong Zhiming . The description is based on an almost completely preserved skeleton ( holotype IVPP V9612) that was discovered in Inner Mongolia, China near the village of Muhuaxiao. Stratigraphically , the find comes from the Ejinhoro Formation in the Ordos Basin .
The only thing missing from the skeleton is the skullcap, cervical and back vertebrae, and a few other bones. The skeleton was found in the same position as the fossil of the relative Mei long : the snout was placed under the left hand. Modern birds adopt a similar posture when they sleep to protect themselves from the cold. This is believed to be yet another indication of the close relationship between birds and dinosaurs. Its fossil skeleton is the best preserved of a troodontid to date.
literature
- Dale A. Russell , Zhi-Ming Dong : A nearly complete skeleton of a new troodontid dinosaur from the Early Cretaceous of the Ordos Basin, Inner Mongolia, People's Republic of China. In: Canadian Journal of Earth Sciences. Vol. 30, No. 10/11, 1993, ISSN 0008-4077 , pp. 2163-2173, doi : 10.1139 / e93-187 .
- Philip J. Currie , Dong Zhiming: New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People's Republic of China. In: Canadian Journal of Earth Sciences. Vol. 38, No. 12, 2001, pp. 1753-1766, doi : 10.1139 / e01-065 .
Web links
Individual evidence
- ^ Alan H. Turner, Diego Pol, Julia A. Clarke, Gregory M. Erickson, Mark A. Norell : A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight. In: Science . Vol. 317, No. 5843, 2007, pp. 1378-1381, doi : 10.1126 / science.1144066 , PMID 17823350 .
- ^ Peter J. Makovicky , Mark A. Norell: Troodontidae. In: David B. Weishampel , Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-06726-6 , pp. 184-195, here p. 193.