Anchisaurus
| Anchisaurus | ||||||||||||
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Skeleton reconstruction of Anchisaurus (after Marsh) |
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| Temporal occurrence | ||||||||||||
| Lower Jurassic ( Pliensbachian to Toarcian ) | ||||||||||||
| 190.8 to 174.1 million years | ||||||||||||
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| Scientific name | ||||||||||||
| Anchisaurus | ||||||||||||
| Marsh , 1885 | ||||||||||||
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Anchisaurus ( synonyms : Megadactylus , Amphisaurus , Yaleosaurus ) was a slender, about 2.5 meters long dinosaur from the group of Plateosauria . He lived in the Lower Jurassic ( Pliensbachian to Toarcian ) about 191 to 174 million years ago. Fossils consisting of almost completely preserved skulls and skeletons were found in the northeastern United States in Massachusetts and Connecticut .
The first fossils of an anchisaurus were discovered as early as 1818, but they were thought to be human bones because at that time no one had any experience with dinosaur fossils. It was not until 1855, after more bones were found, that they were identified as reptile bones. The animal was described in 1865 by Edward Hitchcock and in 1885 by Othniel Charles Marsh .
There is only one sure species, Anchisaurus polycelus . Some bone parts found in South Africa were described as Gyposaurus capensis and in 1971 the new species, Anchisaurus capensis , was assigned, but are considered nomina dubia .
features
Anchisaurus was a small, lightly built dinosaur, about 2.5 meters long and 27 kilograms. Unusually for prosauropods, its cranial windows for the outer nostrils were less than 50 percent the diameter of the bony eye sockets . In the upper jaw he had five teeth on the premaxillary and eleven on the maxillary . The teeth were slender and elongated. The number of teeth in the lower jaw is unknown. The parietal bone consisted of two separate bones.
Whether anchisaurus was a carnivore or a herbivore has not yet been fully clarified. However, since a larger digestive tract is required to digest plants, it is assumed that the prosauropods have developed back to quadruped. Anchisaurus could therefore represent an intermediate stage between four-legged herbivores and two-legged carnivores.
Systematics
Together with Ammosaurus , Anchisaurus forms the family of Anchisauridae within the prosauropods. All taxa that are closer to Anchisaurus than Melanorosaurus are called Anchisauridae .
literature
- Peter Galton , Paul Upchurch : Prosauropoda. 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. 232-258.
- Michael Benton , The Great Colored Dinosaur Lexicon. Special edition. Gondrom, Bindlach 1993, ISBN 3-8112-1099-8 , p. 37.
- Dougal Dixon : dinosaurs. Animals of prehistoric times. Translated by Inge Uffelmann. Bassermann, Niedernhausen / Ts. 1992, ISBN 3-8094-0100-5 , p. 32 f.
Web links
- The Paleobiology Database Anchisaurus
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. 163-164.