Limaysaurus Tessonei

Update: The correct genus is now named Limaysaurus (formerly thought Rebbachisaurus). This article will be updated soon, there is a nice introduction at wikipedia

Up to now, this is the most complete sauropod dinosaur found in South America. There were plenty of sauropods during the Mesozoic era. They were four legged herbivores and big in size. The Rebbachisaurus weighted 10 tons and was medium in size, 17 meters long and related to the famous sauropod Diplodocus from U.S.A. Nevertheless, the specimen from Neuquén was an earlier one. A remarkable difference between both species is that the neural spines of the cervical and dorsal vertebrae of the Rebbachisaurus do not have a "V" shape like the rest of the diplodocus family. Teeth look like slight curved pencils.

The find of the Rebbachisaurus tessonei is of great paleobiographic importance because it is the first time a dinosaur specimen is recorded both in Africa and South America which confirms the connection between both continents. In 1954, in Marruecos, Africa, four bones of a herbivorous dinosaur from the group of sauropods were discovered in rocks of 105 million years of age. They had unique anatomical characteristics which prevented a connection with other sauropods. These materials were named as a new species called Rebbachisaurus garasbae. Till now paleontologists were unable to place this dinosaur, with certainty, in a particular family of sauropods. In 1988, Lieto Francisco Tessone discovered near El Chocón a complete skeleton with a morphology in its anatomy that was very different to the ones known from the end of the last century in this area. This fossil comes from rocks between 100 and 105 million years of age.

A paleontological expedition achieved this year allowed to recover the specimen which was complete in a 90 - 95%, something extremely unusual for a dinosaur of 17 meters long. The study and cleaning work took several years because of the characteristics of the rock. In May 17^th 1996, this dinosaur that lived in the land of Neuquén formally received its name and now can be known at a worldwide level. The study made on the specimen found in Neuquén determined that it is a close relative to the African dinosaur Rebbachisaurus garasbae. That is why the same name -Rebbachisaurus- was given to it. The strong similarities between sauropods from Africa and South America are solid to the proximity of both continents 105 million years ago. Probably, through an intercontinental bridge which would not last long till the final opening of the Atlantic Ocean.

Stomach Stones

Till now the Rebbachisaurus tessonei is the only sauropod in which we can confirm the existence of stomach stones. Apparently, these stones, also called Gastroliths, played the role of grinding the vegetables in the stomach’s interior due to these dinosaurs were unable to chew the food they ate. According to evidence obtained, many sauropods did not have gastroliths and they split up the vegetables through gastric juices and bacteria. The presence of 6 to 7 stomach stones in three out of five found specimens would confirm such evidence, at least in the Rebbachisaurus tessonei.

From Rio Negro Online

Bibliography

Rebbachisaurus tessonei sp. nov. a new sauropoda from the Albian-Cenomanian of Argentina; new evidence on the origin of the Diplodocidae. J.O. Calvo & L. Salgado, Gaia 11 13-33, (1995). Local copy here
The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda). M.P. Taylor & D. Naish, Paleobios 25 1-7, (2005). Local copy here
Lower Cretaceous rebbachisaurid sauropods from Cerro Aguada Del León. L. Salgado, A. Garrido, S.E. Cocca & J.R. Cocca, Journal of Vertebrate Paleontology 24 903-912, (2004)