Limaysaurus

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Limaysaurus
Temporal range: Late Cretaceous, Cenomanian
Limaysaurus.jpg
Skeleton restoration
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Family: Rebbachisauridae
Subfamily: Limaysaurinae
Genus: Limaysaurus
Salgado et al., 2004
Type species
Limaysaurus tessonei
Calvo & Salgado, 1995
Synonyms
  • Rebbachisaurus tessonei

Limaysaurus (“Limay lizard”) is a genus represented by a single species of rebbachisaurid sauropod dinosaurs, which lived during the mid-Cretaceous period, about 99.6 and 97 million years ago, in the Cenomanian, in what is now South America (northwestern Patagonia).

Description[edit]

A Limaysaurus skeleton on display at the National Technical University of Athens, Greece
Skeleton viewed from above, National Technical University of Athens, Greece

Limaysaurus was a medium-sized sauropod. Gregory S. Paul in 2010 estimated its length at fifteen meters (50 ft) and its weight at seven tonnes.[1] The neural spines on its back were very tall. The neural spines of the cervical and dorsal vertebrae are not V-shaped[2] but they have a simple and straight form like an I. Its teeth were curved, unlike those of Diplodocus which were pencil-shaped.[1] Another distinct characteristic of this sauropod is its phylogenetic relationship to Rebbachisaurus from Morocco. This discovery supports the theory that there was a land bridge connecting South America to Africa 100 million years ago.[3] It shared its habitat with Andesaurus and Giganotosaurus, characterized by plains with large and shallow lagoons. The climate was mild and humid. In fossil remains of Limaysaurus, gastroliths have been found, which were used to help the stomach to grind food.

Discovery[edit]

Limaysaurus includes a single type species, Limaysaurus tessonei, which was originally referred to the genus Rebbachisaurus as Rebbachisaurus tessonei, an African species, by Jorge Calvo and Leonardo Salgado in 1995.[4] However, a generic separation was proposed by Salgado, Alberto Garrido, Sergio Cocca and Juan Cocca, and the genus Limaysaurus was named in 2004. The generic name is derived from Río Limay which borders the region and from the specific name, tessonei, in honor of Lieto Tessone, who found the first and most complete holotype.[4] Their discovery shed some light on the distribution of Gondwanan dinosaurs in the mid-Cretaceous period. Several specimens of Limaysaurus are known, one of which (the holotype) is 80% complete, being one of the most complete Cretaceous sauropods ever found in South America.[5][6]

The holotype specimen, MUCPv-205, a partial skeleton including the back of the skull, was found in 1988 by Lieto Francisco Tessone, who is honoured in the specific name. It was afterwards collected, together with MUCPv-206, a second fragmentary skeleton, by José Bonaparte. These two adult specimens likely hailed from the top of the Candeleros Formation, which is dated to the early Cenomanian age. An additional smaller specimen, MUCPv-153, was found nearby, although it belonged to the base of the Huincul Formation, from the late Cenomanian.[4]

Limaysaurus was found 15 km (9 mi) southwest of Villa El Chocón, Picún Leufú Department, Neuquén Province, Patagonia, Argentina.[4] The sediments belong to the Río Limay Subgroup, in Lohan Cura Formation, at Cerro Aguada del León.These beds appear to date from the Aptian-Albian interval,[7] although these fossils were later named Comahuesaurus

Head and neck of a Limaysaurus tessonei in front of a Giganotosaurus

Classification[edit]

The describing authors in 2004 assigned Limaysaurus to the famlily Rebbachisauridae. The rebbachisaurids are a basal clade within the Diplodocimorpha, and their remains have been found in Cretaceous-age rocks in Europe, South America, and Africa. A cladistic analysis of macronarian sauropods (Salgado et al., 2004) demonstrated close affinities between Limaysaurus, the African genera Rebbachisaurus and Nigersaurus, and the South American genera Rayososaurus and Cathartesaura. [7][6]

References[edit]

  1. ^ a b Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press, pp. 186 and 208.
  2. ^ Holmes, Thom (2008). Time of the Giants. USA: Infobase Publishing. p. 48.
  3. ^ Calvo, Jorge and Salgado, Leonardo (1996). A land bridge connection between South America and Africa during Albian-Cenomanian times based on sauropod dinosaur evidences. 39° Congresso Brasileiro de Geología , Anais (7): 392-393.
  4. ^ a b c d Calvo, J. O. and Salgado, L. (1995). "Rebbachisaurus tessonei sp. nov. A new sauropod from the Albian-Cenomanian of Argentina; new evidence on the origin of the Diplodocidae." Gaia, 11: 13-33.
  5. ^ Holtz, Thomas (2012). "Genus List for Holtz (2007) Dinosaurs:The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages" (PDF).
  6. ^ a b Novas, Fernando (2009). The Age of Dinosaurs in South America. USA: Indiana University Press. pp. 175–179.
  7. ^ a b Salgado, L., Garrido, A., Cocca, S. E., and Cocca, J. R. (2004). "Lower Cretaceous rebbachisaurid sauropods from Cerro Aguada Del León, Neuquén Province, northwestern Patagonia, Argentina." Journal of Vertebrate Paleontology, 24(4): 903-912, December 2004.

External links[edit]