Ilokelesia
| Ilokelesia | ||||||||||
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| Temporal occurrence | ||||||||||
| Upper Cenomanium ( Upper Cretaceous ) | ||||||||||
| 95.5 to 93.9 million years | ||||||||||
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| Scientific name | ||||||||||
| Ilokelesia | ||||||||||
| Coria & Salgado , 1998 | ||||||||||
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Ilokelesia is a genus of theropod dinosaur from the group of Abelisauridae . So far only one very fragmentary find is known, which comes from the early Upper Cretaceous ( Upper Cenomanian ) of the Argentine Huincul Formation . The only species is Ilokelesia aguadagrandensis .
The name Ilokelesia comes from the Mapuche language ( ilo - "meat", kelesio - "lizard") and is supposed to indicate a carnivorous reptile. The second part of the species name, aguadagrandensis , points to the locality Aguada Grande .
features
Ilokelesia was a medium-sized theropod. This genus can be distinguished from related genera on the basis of the anatomy of the square leg and the cervical, back and tail vertebrae. For example, when viewed from the side, the cervical vertebrae were more square than rectangular.
Systematics
| Cladogram , simplified from Canale and colleagues, 2008: | ||||||||||||||||||||||||||||||||||||||||||
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| Systematic position of Ilokelesia . |
In the first description by Coria and Salgado (1998) this genus is described as a basal (original) representative of the Abelisauria , a group within the Ceratosauria . According to these researchers, the Abelisauria include Ilokelesia as well as the Abelisauroidea including Noasauridae and Abelisauridae . However, the taxon Abelisauria is rarely used and is rejected by most researchers.
More recent studies, however, classify Ilokelesia as a representative of the Abelis auroid , although the exact relationship is controversial. Carrano and colleagues (2002) and Tykoski and Rowe (2004) see this genus as a basal representative of the Abelisauroidea outside of the Abelisauridae. Carrano and Sampson (2008), on the other hand, see this genus as a derivative of the Abelisauridae and as a sister genus of Carnotaurus ; the basal position in previous analyzes, according to these researchers, is due to the very fragmentary nature of the only known find. Canale and colleagues (2008) also consider Ilokelesia to be derived from Abelisaurids; in this study this genus forms the new group Brachyrostra together with Scorpiovenator , Ekrixinatosaurus , Carnotaurus and Aucasaurus .
Find
The only find ( holotype , specimen number PVPH-35) was discovered in 1991 in the Argentine province of Neuquén south of Plaza Huincul . It was the first finding of a theropod from the Huincul Formation . The fragmentary remains include a few skull bones ( postorbital and square bones ), parts of the cervical, dorsal and caudal vertebrae, cervical ribs, hemal arches , foot bones and two claws. However, as Carrano and Sampson (2008) note, these bones belong to at least two different individuals because three post-orbitals have been discovered. Together with these fossils, a series of vertebrae was recovered that belonged to a third specimen: Although this individual was also an Abelis auroid, it cannot currently be ascribed with certainty to Ilokelesia .
literature
- Juan I. Canale, Carlos A. Scanferla, Federico L. Agnolin, Fernando E. Novas : New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods. In: The natural sciences . Vol. 96, No. 3, 2009, pp. 409-414, doi : 10.1007 / s00114-008-0487-4 .
- 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, here p. 202, doi : 10.1017 / S1477201907002246 .
- Rodolfo A. Coria : Nonavian Theropods. In: Zulma Gasparini, Leonardo Salgado , Rodolfo A. Coria (eds.): Patagonian Mesozoic reptiles. Indiana University Press, Bloomington et al. 2007, ISBN 978-0-253-34857-9 , 229-256.
- Rodolfo A. Coria, Leonardo Salgado: A Basal Abelisauria Novas, 1992 (Theropoda-Ceratosauria) from the Cretaceous of Patagonia, Argentina. In: Gaia. Revista de Geociências. Vol. 15, 1998, ISSN 0871-5424 , pp. 89-102, digital version (PDF; 4.35 MB) .
- Ronald S. Tykoski, Timothy Rowe : Ceratosauria. 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. 47-70.
Individual evidence
- ↑ Coria 2007 , pp. 238-239
- ↑ a b c Coria and Salgado 1998 , pp. 89-91
- ↑ a b Carrano and Sampson 2008 , p. 194
- ↑ a b Canale and colleagues 2008
- ↑ Coria and Salgado 1998 , pp. 96-100
- ^ Paul Sereno : Abelisauria. (No longer available online.) In: Taxon Search. Archived from the original on March 23, 2012 ; accessed on August 6, 2014 . 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 Carrano and Sampson 2008 , p. 202
- ↑ Tykoski and Rowe 2004 , p. 65
