Usually, between one extinction and another, groups of animals reappear. Arcosaurs were some of those that surfaced after the first cataclysmic event and included large predators (but some herbivores), pterosaurs, primitive dinosaurs and crocodile-like animals today – that is to say that crocodilians and birds descend from this species. Finding a fossil record prior to the First Extinction is quite rare. However, recently scientists have found a fossil in the Sanga do Cabral Formation, in Rio Grande do Sul, which is a distant relative of the first arcosaurs: Elessaurus gondwanoccidens. Its name is a tribute to Aragorn, from The Lord of the Rings, which, in other languages created by Tolkien, is called Strider or Elessar. As the fossil points out that the animal had long legs, nothing more appropriate. The species name is derived from the supercontinent Gondwana and from the Latin “occidens”, which means “from the west”. Elessaurus belonged to the genus of Tanytropheus, a group of reptiles with long necks and mainly terrestrial habits. The fossil found had an articulated hind limb, with parts of the pelvis and tail vertebrae. It is believed to have belonged to the Lower Triassic, around 247 million years ago. Most of the fossils of tanstrofeidos have been found in North America, Europe and Asia. The discovery in southern Brazil shows that this genus has spread far more than previously thought. The long legs suggest terrestrial habits, different from later transtrofeidos, which have adapted to a more aquatic life. The discovery of the fossil may still bring more clues about this curious species of reptile.
