Noasaurus
Noasaurus | |
---|---|
Skeletal restoration showing known remains | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | † Abelisauria
|
Family: | †Noasauridae |
Subfamily: | † Noasaurinae
|
Genus: | †Noasaurus Bonaparte & Powell, 1980
|
Species: | †N. leali
|
Binomial name | |
†Noasaurus leali Bonaparte & Powell, 1980
|
Noasaurus ("Northwestern Argentina lizard") is a genus of
Discovery and naming
In the mid-seventies, a fragmentary small theropod skeleton was discovered by
The
In 1999, a neck vertebra found at the site, specimen MACM 622, was identified as oviraptorosaurian, a rare proof that the Oviraptorosauria had invaded the Gondwanan continents.[4] In 2007 however, it was reidentified as a noasaurid vertebra, probably belonging to the Noasaurus holotype.[5]
Description
Noasaurus was a small theropod. Gregory S.Paul estimated its length at 1.5 meters (5 ft), its weight at 15 kg (33 lbs).[6][7]
The maxilla bears at least eleven teeth. The teeth are recurved and have serrations at the front and rear edges.[2]
The neck is probably long as the neck vertebrae are very elongated. These vertebrae are also strongly vertically compressed with a low
While originally reported to have a raptorial 'sickle claw' on the foot similar to the claws of the more advanced dromaeosaurids,[2] subsequent studies showed that the claw actually came from the hand.[8] The claw is exceptionally curved, has parallel base sides in top view, and possesses a deep triangular cavity at the base underside.[3]
Classification
Noasaurus is today considered to be a member of the
The following cladogram is based on the phylogenetic analysis conducted by Rauhut and Carrano in 2016, showing the relationships of Elaphrosaurus among the noasaurids:[9]
Abelisauroidea |
| ||||||||||||||||||||||||||||||||||||||||||
Paleobiology
In 1980, it was thought that the presumed foot claw functioned as a sickle claw.[2] Paul in 1988 saw the noasaurines as the South-American counterparts of the Asian and North-American dromaeosaurids, in a process of convergent evolution. Noting that abelisaurids tend to have very short arms, he wondered whether the forelimbs of Noasaurus were of limited length also, forcing the animal to employ a kicking technique instead of grasping the back of a victim in order to disembowel it with the foot claws, a method he assumed the dromaeosaurids used.[6] This hypothesis was undermined when it was determined that the foot claw was in fact a hand claw.[8]
In 2001, a more complete genus of noasaurid, Masiakasaurus was discovered. This genus had an unusual down-turned jaw and protruding front teeth which would have been well suited to grasping, and Masiakasaurus may have consumed small vertebrates, fish, or invertebrates. Noasaurus may have been similar in appearance and lifestyle.[10]
See also
References
- ^ Bonaparte, J.F., Salfitty, J.A., Bossi, G., Powell, J.E. 1977. "Hallazgos de dinosaurios y aves cretácicas en la Formación Lecho de El Brete (Salta), próximo al límite con Tucumán". Acta Geológica Lilloana 14: 19-28
- ^ a b c d e f J. F. Bonaparte and J. E. Powell. 1980. "A continental assemblage of tetrapods from the Upper Cretaceous beds of El Brete, northwestern Argentina (Sauropoda-Coelurosauria-Carnosauria-Aves)". Mémoires de la Société Géologique de France, Nouvelle Série 139: 19-28
- ^ a b Agnolin, F.L., Apesteguia, S. and Chiarelli, P. 2004. "The end of a myth: The mysterious ungual claw of Noasaurus leali". Journal of Vertebrate Paleontology. 24(3): 301A-302A
- ^ Frankfurt, N.G. and Chiappe, L.M. 1999. "A possible oviraptorosaur from the Late Cretaceous of northwestern Argentina". Journal of Vertebrate Paleontology. 19(1): 101-105
- ^ a b Agnolin, F.L. and Martinelli, A.G. 2007. "Did oviraptorosaurs (Dinosauria; Theropoda) inhabit Argentina?", Cretaceous Research, 28(5): 785-790
- ^ a b c Paul, G.S., 1988, Predatory Dinosaurs of the World. Simon & Schuster, New York, p 285-286
- ^ Paul, Gregory S. (2010). The Princeton Field Guide to Dinosaurs. New Jersey: Princeton University Press. pp. 82.
- ^
- .
Sources
- Lessem, D. (May 1993). "Jose Bonaparte: Master of the Mesozoic". Omni.