Rajasaurus
| Rajasaurus | ||||||||||
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| Temporal occurrence | ||||||||||
| Upper Cretaceous ( Maastrichtian ) | ||||||||||
| 72 to 66 million years | ||||||||||
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| Scientific name | ||||||||||
| Rajasaurus | ||||||||||
| Wilson et al., 2003 | ||||||||||
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Rajasaurus is a genus of theropod dinosaur from the group of Abelisauridae . So far, a single, fragmentary skeleton including cranium is known, which comes from the Upper Cretaceous ( Maastrichtian ) of the Lameta Formation in Gujarat ( India ). The only species is Rajasaurus narmadensis .
The name Rajasaurus ( Sanskrit Rāja - "king", Greek sauros - "lizard") means something like "king lizard", while the second part of the species name, narmadensis , refers to the place where it was found in the Narmada valley.
features
It was a two-legged, approximately 11 m long and 4 ton heavy carnivore. This genus was relatively large and heavily built, the legs were relatively short.
This genus can be distinguished from other genera by three autapomorphies (unique characteristics): On the center line of the skull there is a single, low horn, which is mainly formed by the paired nasal bones (nasals) and to a lesser extent by the paired frontal bones (frontal) . A similar horn is known from some individuals from Majungatholus , but here it largely comes from the frontal bone. Another unique feature is the extremely elongated Fenestra supratemporalis , the upper skull window of the temporal region - in other Abelisaurids this skull window was almost square. A third unique feature is found on the sturdy ilium , where a ridge separates the brevis fossa from the acetabulum .
Meaning and systematics
Rajasaurus is one of the few dinosaur species from the Lameta Formation known for both skull bones and bones of the residual skeleton ( postcranium ), and is therefore of great importance for the understanding of the Cretaceous theropod fauna of India. The eleven named theropod species from the Cretaceous India are largely based on very fragmentary finds and are probably largely identical to each other.
Wilson and colleagues (2003) come to the conclusion that Rajasaurus was a derived (advanced) member of the Abelisauridae, which was closely related to Majungasaurus and Carnotaurus .
Research history and find
The only skeleton to date was discovered by the paleontologist Suresh Srivastava during excavation work in Gujarat, India .
In 1996 Chatterjee and Rudra published a brief description of the find. According to these two researchers, it is an "almost complete skeleton of Indosuchus ". A comprehensive description of the skeleton and the simultaneous first description of the new genus Rajasaurus was carried out in 2003 by researchers working with Jeffrey Wilson .
The site ( Temple Hill ) is near the village of Rahioli in the Narmada Valley . The bones were not found in their original anatomical compound - but since they correspond in size, they are assigned to a single individual. You come from a location of conglomerates . Above this layer follows a layer of calcareous sandstones that contained dinosaur teeth, as well as a layer of dinosaur eggs and nests.
The only specimen (holotype, specimen number GSI 21141 / 1-33) includes a cerebral skull, vertebrae (fragmentary dorsal vertebrae, one fragment each of a cervical and caudal vertebrae, sacral vertebrae), pelvic bones (the right and left iliac bones) and a pubic bone Fragment (pubis)), leg bones (both thigh bones (femora), shinbone (tibia), fibula) and metatarsal bone (metatarsals).
supporting documents
literature
- Jeffrey A. Wilson, Paul C. Sereno , Suresh Srivastava, Devendra K. Bhatt, Ashu Khosla, Ashok Sahni: A new abelisaurid (Dinosauria, Theropoda) from the Lameta Formation (Cretaceous, Maastrichtian) of India (= The University of Michigan. Contributions from the Museum of Paleontology. Vol. 31, No. 1, 2003, ISSN 0097-3556 ). The University of Michigan - Museum of Paleontology, Ann Arbor MI 2003, online .
- Matthew T. Carrano, Scott D. Sampson: The Phylogeny of Ceratosauria (Dinosauria: Theropoda). In: Journal of Systematic Palaeontology. Vol. 6, No. 2, 2008, ISSN 1477-2019 , pp. 183-236, doi : 10.1017 / S1477201907002246 .
Individual evidence
- ^ A b Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 80, online .
- ↑ a b c d e f Wilson et al. 2003 , pp. 4-9
- ↑ a b Wilson et al. 2003 , pp. 3-4
- ↑ Carrano et al. 2008 , p. 197
- ↑ Wilson et al. 2003 , pp. 25-26
