Aucasaurus
Aucasaurus | ||||||||||||
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Aucasaurus skeletal reconstruction |
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Temporal occurrence | ||||||||||||
Upper Cretaceous (Lower to Middle Campanium ) | ||||||||||||
83.6 to 76.4 million years | ||||||||||||
Locations | ||||||||||||
Systematics | ||||||||||||
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Scientific name | ||||||||||||
Aucasaurus | ||||||||||||
Coria , Chiappe & Dingus , 2002 | ||||||||||||
Art | ||||||||||||
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Aucasaurus is a genus of theropod dinosaur from the group of Abelisauridae . The only known skeleton comes from the Upper Cretaceous (Lower to Middle Campanium ) of the Argentine site of Auca Mahuevo , which is famous for its numerous finds of sauropod eggs and embryos. It is a well-preserved, almost complete skeleton including skin and tissue impressions. This find offers insights into various previously poorly understood aspects of the anatomy of the Abelisauridae, especially the greatly reduced arms, and is therefore of high scientific value. Aucasaurus wasprovisionally described scientificallyin 2002 by researchers around Rodolfo Coria with the only species Aucasaurus garridoi . A comprehensive description is currently being prepared (as of 2008).
The name Aucasaurus comes from the Mapuche language and points to the site of Auca Mahuevo. The second part of the species name, garridoi , honors Alberto Garrido, the discoverer of the skeleton.
features
Aucasaurus , like other Abelisaurids, was a two-legged carnivore with a relatively short skull and short, reduced arms. The skeleton found is 30% smaller than that of the closely related Carnotaurus . The legs were relatively slim - similar to Carnotaurus , but different from Majungasaurus . Compared to Carnotaurus , Aucasaurus was less specialized: While Carnotaurus had a pair of large frontal horns extending from the frontal bone , Aucasaurus only had low protrusions. The snout, which is higher than long in Carnotaurus , is relatively longer in Aucasaurus . The arms were shortened in both genera; relative to the thigh bone, however, the arms of Aucasaurus were longer than those of Carnotaurus .
The metacarpal bones (metacarpals) are articulated directly with the forearm , as in Carnotaurus ; Carpal bones (carpalia) are missing. The hand has four rays: the first and fourth rays consist of only one metacarpal bone each, while the second and third ray each have one and two small finger bones (phalanges). As with Carnotaurus , the fourth metacarpal shows a conical end. However, in Aucasaurus the first metacarpal bone is the longest bone of the hand, not the fourth as in Carnotaurus .
Systematics
Aucasaurus is often classified as a sister genus of Carnotaurus within the Abelisauridae .
Find
The only skeleton was discovered in March 1999 during a paleontological expedition. The skeleton ( holotype , specimen number MCF-PVPH-236) was found in the anatomical network and lying on the right side. It probably belonged to an adult individual, which is indicated by the degree of fusion of individual bone sutures on the skeleton.
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, doi : 10.1017 / S1477201907002246 .
- Rodolfo A. Coria , Luis M. Chiappe , Lowell Dingus : A new close relative of Carnotaurus sastrei Bonaparte 1985 (Theropoda: Abelisauridae) from the Late Cretaceous of Patagonia. In: Journal of Vertebrate Paleontology. Vol. 22, Vol. 2, 2002, pp. 460-465, doi : 10.1671 / 0272-4634 (2002) 022 [0460: ANCROC] 2.0.CO; 2 .
- Javier Ruiz, Angélica Torices, Humberto Serrano, Valle López: The hand structure of Carnotaurus sastrei (Theropoda, Abelisauridae): implications for hand diversity and evolution in abelisaurids. In: Palaeontology. Vol. 54, No. 6, 2011, ISSN 0031-0239 , pp. 1271-1277, doi : 10.1111 / j.1475-4983.2011.01091.x .
Individual evidence
- ↑ a b c Carrano and Sampson 2008 , p. 191
- ↑ a b c d Coria et al. 2002
- ↑ Ruiz et al. 2011
- ↑ Canale et al. 2009