Andesaurus
Andesaurus | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | †Sauropodomorpha |
Clade: | †Sauropoda |
Clade: | †Macronaria |
Clade: | †Titanosauria |
Genus: | †Andesaurus Calvo & Bonaparte, 1991 |
Species: | †A. delgadoi
|
Binomial name | |
†Andesaurus delgadoi Bonaparte , 1991 |
Andesaurus (
History of discovery
In 1991,
The only known material of Andesaurus is a partial skeleton consisting of a series of four
Description
Total length estimates place Andesaurus at 15 metres (49 ft)[2] to 18 metres (59 ft) long.[3] Gregory S. Paul lists Andesaurus as 7 metric tons (7.7 short tons) in body mass.[2]
The
Tail vertebrae (caudals) of Andesaurus are slightly procoelous, where the anterior face is concave and the posterior face of convex. This convexity is less prominent than more derived titanosaurs, but is still diagnostic of the clade as a whole. The first caudal has a flat anterior and slightly convex posterior face, different from the subsequent vertebrae similar to in Epachthosaurus. A prominent depression is present on the bottom surface of some anterior caudals, a feature present in diplodocids and multiple titanosaurs. Anterior caudals are shorter proportionally, the bones becoming almost double the proportional length towards the end of the tail. Lateral pleurocoels are present on some vertebrae, as well as small lateral foramina. These foramina are known in some titanosaurs and non-titanosaurs, but their phylogenetic distribution is poorly understood. Like in all titanosauriformes, the neural arch is on the anterior portion of the centrum, and the neural spines are elongate and rectangular. The variation along the caudal series is similar to Epachthosaurus and Malawisaurus.[4]
Classification
Several plesiomorphic (primitive) features characterize Andesaurus as the most basal known member of Titanosauria. In fact, this
Some other basal titanosaurs from Argentina, including Argentinosaurus and Puertasaurus, were also sauropods of enormous size. The most derived group of titanosaurs, the Saltasauridae, included some of the smallest known sauropods, including Saltasaurus itself. Thus it is possible that the largest sizes were attained among the more basal members of the clade.[7]
Palaeoecology
These fossils were discovered in the
References
- ^ "Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 145.
- ^ a b Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 205
- ^ a b Holtz, Thomas R. Jr. (2012) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix.
- ^ .
- ^ Salgado, et al. (1997). Wilson and Upchurch (2003).
- ^ Upchurch, et al. (2004).
- ^ Novas, et al. (2005).
Bibliography
- Novas, F.E., Salgado, L., Calvo, J.O., & Agnolin, F. 2005. Giant titanosaur (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia. Revista del Museo Argentino de Ciencias Naturales 7(1): 37-41.
- Salgado, L., Coria, R.A., & Calvo, J.O. 1997. Evolution of titanosaurid Sauropods. I: Phylogenetic analysis based on the postcranial evidence. Ameghiniana. 34: 3-32.
- Tidwell, V., Carpenter, K. & Meyer, S. 2001. New Titanosauriform (Sauropoda) from the Poison Strip Member of the Cedar Mountain Formation (Lower Cretaceous), Utah. In: Mesozoic Vertebrate Life. D. H. Tanke & K. Carpenter (eds.). Indiana University Press, Eds. D.H. Tanke & K. Carpenter. Indiana University Press. 139-165.
- Upchurch, P., Barrett, P.M, & Dodson, P. 2004. Sauropoda. In: Weishampel, D.B., Dodson, P., & Osmolska, H. (Eds.). The Dinosauria (2nd Edition). Berkeley: University of California Press. Pp. 259–322.
Further reading
- Calvo, J.O. & Bonaparte, J.F. 1991. "Andesaurus delgadoi gen. et sp. nov. (Saurischia-Sauropoda), dinosaurio Titanosauridae de la Formacion Rio Limay (Albiano-Cenomaniano), Neuquén, Argentina" [Andesaurus delgadoi n. g. n. sp. (Saurischia, Sauropoda) a titanosaurid dinosaur from the Río Limay Formation (Albian-Cenomanian), Neuquén, Argentina.] Ameghiniana. 28: 303-310. [In Spanish]
- Wilson, J.A. & Upchurch, P. 2003. A revision of Titanosaurus Lydekker (Dinosauria – Sauropoda), the first dinosaur genus with a ‘Gondwanan’ distribution. Journal of Systematic Palaeontology 1(3): 125–160.