Amargasaurus

Amargasaurus; Temporal range: Lower Cretaceous ; 130–125 mya
Scientific classification
Kingdom:	Animalia
Class:	Sauropsida
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Sauropodomorpha
Infraorder:	Sauropoda
Superfamily:	Diplodocoidea
Family:	Dicraeosauridae
Genus:	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 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]^{:&hairsp;Script error: The function "hyphen2dash" does not exist.&hairsp;} 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]^{:&hairsp;Script error: The function "hyphen2dash" does not exist.&hairsp;} They were circular in cross section and tapered towards their tips.^[1]^{:&hairsp;Script error: The function "hyphen2dash" does not exist.&hairsp;} The tallest spines could be found on the middle part of the neck, where they reached 60 cm on the 8th cervical.^[1]^{:&hairsp;Script error: The function "hyphen2dash" does not exist.&hairsp;} On the neck, they were bowed backwards, projecting above the adjacent vertebra.^[2]^{:&hairsp;Script error: The function "hyphen2dash" does not exist.&hairsp;} 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]^{:&hairsp;Script error: The function "hyphen2dash" does not exist.&hairsp;}

Amargasaurus Media

Size comparison of the Dicraeosauridae members. Amargasaurus is green.
Neck vertebrae of the holotype, with cross-section reconstruction of soft-tissue
Skeletal reconstruction, with known elements in white
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
Life restoration of a pair of displaying Amargasaurus with "cervical sails" based on Cerda and colleagues, 2022
Life restoration of Amargasaurus without the proposed "cervical sail"
Skeleton cast showing the neck spikes pointing forwards during downwards bending, Museum of Paleontology Egidio Feruglio
Reconstructed Amargasaurus skull.

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]

[novas2009-1] 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

[upchurch2004-2] 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.

[bailey1997-3] Bailey, Jack Bowman 1997. Neural spine elongation in dinosaurs: sailbacks or buffalo-backs?. Journal of Paleontology 71 (6): 1124–1146. [1]

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