Riojasaurus

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Riojasaurus Fossil range: Late Triassic
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Dinosauria Order: Saurischia Suborder: Sauropodomorpha Infraorder: Prosauropoda Family: Riojasauridae Genus: Riojasaurus Bonaparte, 1969
Species
R. incertus Bonaparte, 1969 (type)

Riojasaurus (meaning "Rioja lizard") was a herbivorous prosauropod dinosaur named after La Rioja Province in Argentina where it was found by José Bonaparte. It lived during the Late Triassic and grew to about 11 metres long (37 ft). Riojasaurus had a heavy body, bulky legs, and a long neck and tail. It probably moved slowly on all fours and was unable to rear up on its back legs.^[1] Experts think that Riojasaurus probably travelled in herds for protection^{[citation needed]}. Unlike smaller prosauropods such as Plateosaurus, Riojasaurus could not rear up on its hind legs^{[citation needed]}. No skull was found with the first skeleton of Riojasaurus, but its long slender neck suggests that its head was quite small. Riojasaurus is the only known Riojasaurid to live in South America.

The teeth of Riojasaurus were leaf shaped and serrated. The upper jaw contained 5 teeth at the front, with 24 more behind them in a row that ended under the eyes. Many scientists think that Riojasaurus was closely related to Melanorosaurus, the largest prosauropod known from the Triassic-Early Jurassic era. However, studies at Bristol University, England, suggest that it is unique in some key ways, such as the longer bones in its neck. It is certainly quite different from other prosauropods found in the Los Colorados Formation of Argentina. ^[2]

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