Rinconsaurus

Taxobox
name = "Rinconsaurus"
fossil_range = Late Cretaceous


image_width = 250px
image caption = "Rinconsaurus"
regnum = Animalia
phylum = Chordata
classis = Sauropsida
superordo = Dinosauria
ordo = Saurischia
subordo = Sauropodomorpha
infraordo = Sauropoda
unranked_familia = Titanosauria
familia = unknown
genus = "Rinconsaurus"
genus_authority = Calvo & Riga, 2003
subdivision_ranks = Species
subdivision =
* "R. caudamirus" Calvo & Riga, 2003 (type)

"Rinconsaurus" is a genus of dinosaur from the Late Cretaceous. It was a titanosaurid sauropod which lived in what is now Argentina. The type species, "Rinconsaurus caudamirus", was described by Calvo and Riga in 2003, and is based on three partial skeletons.

Description

Like all sauropods, "Rinconsaurus" was a large long-necked quadrupedal animal, with a long, whip-like tail and four pillar-like legs. "Rinconsaurus" was an unusually slender sauropod. Although fossil discoveries are incomplete, and no complete necks or heads have been found, fully grown "Rinconsaurus" are estimated to have been 11 meters (36 ft) long and approximately 2.5 meters (8 ft) high at the shoulder.cite journal| last =Coria| first =Jorge| authorlink =| coauthors =B.J.G. Riga| title ="Rinconsaurus caudamirus gen. et sp nov.", a new titanosaurid (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia, Argentina| journal =Revista Geologica de Chile | volume =30| issue =2| pages =333–353| publisher =| date =2003| url =http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082003000200011&lng=es&nrm=iso&tlng=en| doi =| id =ISSN 0716-0208| accessdate =2007-05-21] Though only a portion of one skull has been recovered, "Rinconsaurus" may have had a long, narrow skull, based on fossil evidence of the skulls of related titanosaurs.

Discovery and species

Fossils of "Rinconsaurus" were discovered in 1997 by Gabriel Benítez near Rincón de los Sauces, in the Neuquen province of Argentina. The fossils, which consisted of three individuals (two adults and one juvenile), were excavated by Jorge Calvo of the Paleontology Museum of the National University of Comahue.

The type, and only known species, "Rinconsaurus caudamirus", was described by Calvo and Bernardo J. González Riga of the Paleovertebrate Laboratory in Mendoza, Argentina, in 2003. The authors noted derived traits unique to the genus, including distinctive tail vertebrae with bony processes. The fossil remains included vertebrae, limb bones, scapula, hip bones (pubis, ilium, and ischium) and several ribs. Cranial fragments, a mandible, and two teeth have also been discovered. These teeth resemble those of another titanosaurid, "Malawisaurus dixeyi".

The generic name refers to Rincón de los Sauces, where the fossils were discovered, while the specific name, "caudamirus", means "amazing tail", in reference to the unusual shape of the tail vertebrae.

Classification

"Rinconsaurus" is a titanosaurid sauropod. Within the titanosaurs, Coria and Riga regard this dinosaur as closely related to "Aeolosaurus" based on several derived traits. In 2007, Casal "et al." assigned "Rinconsaurus", "Gondwanatitan", and "Aeolosaurus" to Aeolosaurini, a proposed stem-based clade of titanosaurs.Casal, G.; Martínez, R.D.; Luna, M.; Sciutto, J.C; and Lamanna, M.C. (2007). "Aeolosaurus colhuehuapensis sp. nov." (Sauropoda, Titanosauria) de la Formación Bajo Barreal, Cretácico Superior de Argentina ["Aeolosaurus colhuehuapensis sp. nov". (Sauropoda, Titanosauria) from the Bajo Barreal Formation, Upper Cretaceous of Argentina] ". "Revista Brasileira de Paleontologia" 10(1):53-62] It remains to be seen, however, if this classification will receive wide-spread acceptance.

Paleobiology

Diet

"Rinconsaurus", like all sauropods, was an herbivore. Fossilized dung associated with late Cretaceous titanosaurids has revealed phytoliths, silicified plant fragments, that offer clues to a broad, unselective plant diet. Besides the plant remains that might have been expected, such as cycads and conifers, discoveries published in 2005 revealed an unexpectedly wide range of monocotyledons, including palms and grasses (Poaceae), including ancestors of rice and bamboo, which has given rise to speculation that herbivorous dinosaurs and grasses co-evolved.Citation| last =Prasad| first =V.| author-link =| last2 =Caroline A. E. Strömberg, Habib Alimohammadian, and Ashok Sahni | first2 =| author2-link =| title =Dinosaur Coprolites and the Early Evolution of Grasses and Grazers | journal =Science| volume =310| issue =5751| pages =1177-1180| date =| year =2005| url =http://www.sciencemag.org/cgi/content/abstract/310/5751/1177| doi =10.1126/science.1118806| id =]

Titanosaurid teeth are usually spatulate (spoon-shaped) or shaped like pegs. Teeth found in association with "Rinconsaurus" have been described as "pencil-chisel-like teeth" and had sharply inclined wear facets. Without the ability to grind food, "Rinconsaurus", like other sauropods, would have stripped foliage.

References

ee also

External links

* [http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082003000200011&lng=es&nrm=iso&tlng=en "Rinconsaurus caudamirus gen. et sp. nov.", a new titanosaurid (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia, Argentina] Original paper describing "Rinconsaurus" (technical)
* [http://www.users.qwest.net/~jstweet1/saltasauridae.htm Saltasauridae] from "Thescelosaurus!"
* [http://www.dinodata.org/index.php?option=com_content&task=view&id=7315&Itemid=67 "Rinconsaurus"] DinoData.org