Anchisauridae
| Anchisauridae | ||||||||||||
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Anchisaurus skeletal reconstruction |
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| Temporal occurrence | ||||||||||||
| Lower Jurassic ( Pliensbachian to Toarcian ) | ||||||||||||
| 190.8 to 174.1 million years | ||||||||||||
| Locations | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Anchisauridae | ||||||||||||
| Marsh , 1885 |
The Anchisauridae is a group of sauropodomorphic dinosaurs first proposed by Othniel Charles Marsh in 1885 . This family includes Anchisaurus and its closest relatives; according to the latest definition, the group includes Anchisaurus and Ammosaurus . Both genera come from the Lower Jurassic North America.
Validity, Definition and History of Research
The validity of this group is disputed; it is only used occasionally in current specialist literature. Paul Sereno (1999) considers the type material of Anchisaurus to be non-diagnostic, which means that there are no features that can be used to distinguish the genus from other genera such as the related Ammosaurus . He consequently regards the Anchisauridae as invalid. Peter Galton and Paul Upchurch (2004) meanwhile list the Anchisauridae as a valid group and define them as all genera that are more closely related to Anchisaurus than to Melanorosaurus .
Various authors assigned other genera to this group in addition to Anchisaurus , but these assignments vary depending on the author. Othniel Charles Marsh initially set up this group as a monotypical taxon that only contained the Anchisaurus described by him at the same time . Marsh initially gave this group the name Amphisauridae, and Anchisaurus himself he initially called Amphisaurus . When it later turned out that the name Amphisaurus was already taken, both names were changed to Anchisaurus and Anchisauridae. Galton (1990) also listed Anchisaurus as the only genus in this group. Stell (1970) meanwhile ascribed the genera Thecodontosaurus and Massospondylus to the group in addition to Anchisaurus . The most recent study, which recognizes the Anchisauridae as valid, comes from Galton and Upchurch (2004). These authors assign the two genera Anchisaurus and Ammosaurus to it. Ammosaurus has already been discovered by Marsh, but he described it as another species of Anchisaurus .
features
Galton and Upchurch (2004) give various jointly derived characteristics ( synapomorphies ) by means of which the group should be distinguished from other groups. The length-height ratio of the longest postaxial cervical vertebra is at least 3.0. The deltopectoral ridge, a bone ridge of the upper arm bone (humerus), ends at half the length of the humerus. The pre- acetabular process of the iliac bone ends before the distal end of the pubic process; Both bone ridges, viewed from the side, are also at a narrow angle to one another.
Systematics
Traditionally, this group is counted among the prosauropods , which are regarded as a precursor group or sister group of the sauropods . It is currently controversial whether the prosauropods are a monophyletic group. A recent study by Adam Yates concludes that Anchisaurus was actually closely related to sauropods, much closer than prosauropods such as Plateosaurus .
Web links
- Anchisauridae in The Paleobiology Database
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, online .
- ^ Othniel C. Marsh : Names of extinct reptiles. In: American Journal of Science. Vol. 129 = Series 3, Vol. 29, No. 170, 1885, p. 169, digitized .
- ↑ a b Paul Sereno: Anchisauridae. (No longer available online.) In: Taxon Search. Archived from the original on March 23, 2012 ; Retrieved November 22, 2010 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ A b c 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.
- ^ Adam M. Yates: A revision of the problematic sauropodomorph dinosaurs from Manchester, Connecticut and the status of Anchisaurus Marsh. In: Palaeontology. Vol. 53, No. 4, 2010, ISSN 0031-0239 , pp. 739-752, doi : 10.1111 / j.1475-4983.2010.00952.x .
