Rayososaurus

Rayososaurus is an extinct genus of sauropod dinosaur in the family Rebbachisauridae. Rayososaurus was named by Argentinian paleontologist José Bonaparte in 1996. Its type and only accepted species is Rayososaurus agrioensis. The species Limaysaurus tessonei was at one point included in Rayososaurus as Rayososaurus tessonei.

==History of discovery== The only known specimen of Rayososaurus agrioensis was discovered in 1991 by a team led by José F. Bonaparte, at a locality three kilometers south of Agrio del Medio in Picunches Department, Neuquén Province, Argentina. In 1996, Bonaparte described the remains as a new genus and species of sauropod, Rayososaurus agrioensis. Bonaparte believed that the strata the specimen was excavated from belonged to the Rayoso Formation, and named the genus after it. The species name refers to the Agrio River, which the specimen was found near. Bonaparte argued that the distinctive morphology of the scapula indicated that Rayososaurus was closely related to Rebbachisaurus, which was considered a diplodocid at the time, and suggested that the two probably represent a previously unrecognized clade of sauropods distinct from diplodocids. The following year, Bonaparte proposed the family Rebbachisauridae to encompass Rayososaurus and Rebbachisaurus. Efforts undertaken in 2008 and 2009 re-located the original locality and determined that the specimen actually came from the upper layers of the Candeleros Formation.