The Riojasaurus name means Rioja Lizard. This herbivore was named after the La Rioja Province located in Argentina. The first fossil structure of the Riojasaurus was discovered by a Famous Argentine paleontologist José Bonaparte. The first discovery was near complete but not with a skull, although today there is over 15 complete skeleton fossils that were discovered in the foothills of the Andes.

Riojasaurus was not a typical Sauropod in the suborder of prosauropod. It was different by longer bones in the neck. It was definatly a close relative to Melanorosaurus, another Sauropod.

Riojasaurus had a long neck, strong legs, heavy build, long tail, walked on four legs, leaf shaped teeth, and was about 10 meters long as be adult.