Riojasaurus incognitus is an enigmatic dinosaur that has been shrouded in mystery for centuries. Discovered in the late 19th century in the Rioja region of Spain, this dinosaur has been the subject of much speculation
From Wikipedia
Riojasaurus was a herbivorous sauropodomorph dinosaur named after La Rioja Province in Argentina where it was found in the Los Colorados Formation in the Ischigualasto-Villa Unión Basin by José Bonaparte. It lived during the Late Triassic and grew to about 6.6 metres (22 ft) long. Riojasaurus is the only known riojasaurid to live in South America.