Austroraptor
| Austroraptor Temporal range: Late Cretaceous,
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Scientific classification 
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| Missing taxonomy template (fix): | Austroraptor cabazai |
Austroraptor ("Southern thief") was a genus of dromaeosaurid dinosaur that lived about 70 million years ago during the Cretaceous period in what is now modern Argentina. The type species for the genus, Austroraptor cabazai, was described in late 2008 by Fernando Novas of the Museo Argentino de Ciencias Naturales. The fossil specimen was discovered in the Late Cretaceous deposits located in the Río Negro Province of Argentina.[1] The species was named in honor of Alberto Cabaza, who founded the Museo Municipal de Lamarque where the specimen was partially studied.[2][3]
Anatomy
Considered large for a dromaeosaur, Austroraptor cabazai measured around 5 metres (16 ft) in length from head to tail. It is the largest dromaeosaur to be discovered in the Southern Hemisphere.[1] Particularly notable about the taxon were its relatively short forearms, much shorter in proportion compared to those of other members of its family. The relative length of its arms has caused Austroraptor to be compared to another, more famous short-armed dinosaur, Tyrannosaurus.[4]
The type specimen, labeled MML-195, consisted of a fragmentary skeleton including parts of the dinosaur's skull, a few neck and torso vertebrae, some ribs, a humerus, and assorted bones from both legs. The remains were found among deposits of the Allen Formation of Argentina, dating from the Campanian to the Maastrichtian stages of the Late Cretaceous period 70 million years ago. However little of the entire skeleton was found, what bones were available for analysis expressed some distinct characteristics that differentiate Austroraptor from other dromaeosaurs. A. cabazai's 80 centimeter-long skull was low and elongated, much more so than that of other dromaeosaurs. Several of its skull bones bore some resemblance to that of the smaller troodontid deinonychosaurs. The front limbs of this taxon were short for a dromaeosaur, with its humerus less than half the length of its femur.[1] Austroraptor had conical, non-serrated teeth, which Novas et al. compared to those of spinosaurids.[1]
Phylogeny
A cladistic analysis of the specimen's anatomical features by the describers placed Austroraptor within the subfamily Unenlagiinae of the Dromaeosauridae. Some of these characteristics include the geometry and formation of the specimen's vertebral elements. It was determined that Austroraptor was a close relative of the unenlagiine dromaeosaur Buitreraptor.[1]
References
- ^ a b c d e Novas, Fernando E. (2008-12-16). "A bizarre Cretaceous theropod dinosaur from Patagonia and the evolution of Gondwanan dromaeosaurids". Proceedings of the Royal Society B. 276 (1659). The Royal Society: 1101–7. doi:10.1098/rspb.2008.1554. PMC 2679073. PMID 19129109. Retrieved 2008-12-18.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ "Descubrimiento de un dinosaurio "raptor" gigante en el norte de Patagonia" (Press release). Museo Argentino de Ciencias Naturales. 2008-12-17. Retrieved 2008-12-17.
- ^ "New dinosaur species similar to T.rex is uncovered in Argentina". Science & Tech. the Daily Mail. 2008-12-17. Retrieved 2008-12-18.
- ^ "Researchers find short-armed raptor in Argentina". Reuters. 2008-12-16. Retrieved 2010-11-10.
