Shenzhousaurus
Shenzhousaurus | ||||||||||||
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Artistic reconstruction of life by S. orientalis . Scale 1 meter. |
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Temporal occurrence | ||||||||||||
Lower Cretaceous ( Barremium ) | ||||||||||||
130.7 to 126.3 million years | ||||||||||||
Locations | ||||||||||||
Systematics | ||||||||||||
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Scientific name | ||||||||||||
Shenzhousaurus | ||||||||||||
Ji et al. , 2003 |
Shenzhousaurus is a genus of theropod dinosaurs in the ornithomimosauria group from the Lower Cretaceous of East Asia. He is considered to be one of the oldest and most primeval representatives of this group.
features
From shenzhousaurus an incomplete skeleton is known so far in which the skull was damaged and the lower parts of the legs, the rear part of the tail were missing and parts of the front limbs. Like all ornithomimosaurs, it should have moved biped (on two legs), with the hind legs being significantly longer than the front legs. The front legs were large, but delicately built - in contrast to later ornithomimosaurs, the metacarpal bone of the thumb was even shorter than the other two. Another primal feature is that this dinosaur still had teeth in the front part of the lower jaw - the upper jaw was toothless. There were around nine small, conical, not serrated teeth per half of the jaw. In the stomach region remains of gastroliths (stomach stones) were discovered, which could be an indication that Shenzhousaurus ate plants. The specimen has a posture similar to the Opisthotonus . This curved posture of the neck, including the head and tail, is not due to agony , but to the decomposition processes after death.
Discovery and naming
The fossil remains of Shenzhousaurus were discovered in the Yixian Formation in the Chinese province of Liaoning and first described in 2003 . The name is derived from an old name for the country China. The type and only known species is Shenzhousaurus orientalis . The find is dated in the Lower Cretaceous ( Barremium ) to an age of around 130 to 126 million years. This makes it, together with Kinnareemimus and Pelecanimimus, the oldest known representative of the ornithomimosauria.
Systematics
Shenzhousaurus is after Pelecanimimus as the most basic representative of the Ornithomimosauria and apart from this as a sister taxon of the other genera of this group. The primeval features include the dentition (except for pelecanimimus and harpymimus , all other representatives are toothless), the ischial bone in the pelvis , which is straight and not yet bent forward, and the first metacarpal bone, which was not as long as the others.
literature
- Qiang Ji, Mark A. Norell , Peter J. Makovicky , Ke-Qin Gao, Shu'An Ji, Chongxi Yuan: An Early Ostrich Dinosaur and Implications for Ornithomimosaur Phylogeny (= American Museum Novitates. No. 3420, ISSN 0003-0082 ) . American Museum of Natural History, New York NY 2003, online .
- Peter J. Makovicky, Yoshitsugu Kobayashi, Philip J. Currie : Ornithomimosauria. 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. 137-150.
- Achim G. Reisdorf, Michael Wuttke : Re-evaluating Moodie's Opisthotonic-Posture Hypothesis in Fossil Vertebrates Part I: Reptiles - the taphonomy of the bipedal dinosaurs Compsognathus longipes and Juravenator starki from the Solnhofen Archipelago (Jurassic, Germany). In: Palaeobiodiversity and Palaeoenvironments. Vol. 92, No. 1, 2012, ISSN 1867-1594 , pp. 119-168, doi : 10.1007 / s12549-011-0068-y .
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 , p. 111, online .