Amargasaurus
Amargasaurus was a sauropod from the early Cretaceous period. It grew to 10 meters (33 feet) length, which was relatively small for a sauropod. It was a quadrupedal herbivore with a long, low skull on the end of a long neck, much like its relative Dicraeosaurus.
| Amargasaurus Temporal range: Lower Cretaceous
130–125 mya | |
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| Genus: | Amargasaurus
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Amargasaurus was found in La Amarga, a canyon in Neuquén Province, Argentina.
Features
Amargasaurus had two tall rows of spines on top of its backbone along the neck and back.[1]:174 The function of the spines is not known. They may have operated as a defence from theropod attack from above. Another idea is that they supported a sail-like structure.
The neural spines were bifurcated along their entire length, forming a double row.[1]:174 They were circular in cross section and tapered towards their tips.[1]:174 The tallest spines could be found on the middle part of the neck, where they reached 60 cm on the 8th cervical.[1]:174 On the neck, they were bowed backwards, projecting above the adjacent vertebra.[2]:304 Greatly elongated spines continue along the last two dorsal vertebrae, the hip and foremost tail. However, in these regions the spines were not bifurcated but flared into a paddle-shaped upper end.[3]:1139
Amargasaurus Media
Size comparison of the Dicraeosauridae members. Amargasaurus is green.
Neck vertebrae of the holotype, with cross-section reconstruction of soft-tissue
Life restoration of a pair of displaying Amargasaurus with "cervical sails" based on Cerda et al. 2022
Casts of Amargasaurus and Carnotaurus, both discovered by the same 1984 expedition in Argentina, Natural History Museum of the University of Pisa
Skull reconstruction, redrawn after, showing known material (brown) and the location of the various skull openings. Missing parts are reconstructed after Dicraeosaurus.
Size comparison between a human, Dicraeosaurus, Amargasaurus, and Brachytrachelopan
Skeleton cast showing the neck spikes pointing forwards during downwards bending, Museum of Paleontology Egidio Feruglio
Life restoration of Amargasaurus without the proposed "cervical sail"
Reconstructed Amargasaurus skull.
Hind view of skeleton, showing the pelvis and tall sacral spines
References
- ↑ 1.0 1.1 1.2 1.3 Novas, Fernando E. 2009. The age of dinosaurs in South America. Bloomington: Indiana University Press. ISBN 978-0-253-35289-7
- ↑ Upchurch P; Barrett P.M, & Dodson P. 2004. Sauropoda. In: Weishampel D.B; Dodson P. & Osmolska H. (eds) The Dinosauria. 2nd ed, Berkeley: University of California Press, 259–322.
- ↑ Bailey, Jack Bowman 1997. Neural spine elongation in dinosaurs: sailbacks or buffalo-backs?. Journal of Paleontology 71 (6): 1124–1146. [1]