Paleontologists in Brazil have discovered a new species of dinosaur that came to prominence in South America in the wake of the end-Triassic mass extinction event, the first of five major extinctions that shaped life on Earth.
Unlike the Earth's most recent mass extinction -- the end-Cretaceous climatic transformation that killed off the dinosaurs some 67 million years ago -- this original event permitted the 150-million-year-plus reign of the dinosaurs. And the puma-sized Tachiraptor admirabilis was one of the first to take advantage of the transformed landscape.
Although it's not certain what caused this initial extinction event, it's likely an uptick in volcanic activity played a significant role. Regardless of the trigger, the result was simple -- a diminished playing field allowed dinosaurs to suddenly rise to the top of the food chain. Small dinos like the Tachiraptor admirabilis relished a habitat suddenly rid of a number of reptile groups and other potential competitors.
Scientists' new understanding of this species, time period and region was made possibly by the recent discovery of Tachiraptor admirabilis bones, unearthed in the foothills of the northern Andes in Venezuela. The fossils date to roughly 200 million years ago -- the beginning of the Jurassic period and the start of the dinosaurs' rise to global dominance. Only one other dinosaur has ever been discovered from this region, the fox-sized Laquintasaura venezuelae.
"Laquintasaura may have been part of Tachiraptor's diet," study author Max Langer, a vertebrate paleontologist at the University of São Paulo in Brazil, told Live Science. "Tachiraptor was probably a generalist predator that ate anything it could get, such as small dinosaurs and other vertebrates, such as lizards."
Because so few dinosaurs have been discovered in this region of South America -- which during the Jurassic period was still part of Pangaea -- scientists had assumed the habitat was too harsh for dinosaurs to thrive. But the discovery of Tachiraptor suggest there may have been more biodiversity present than recently thought.
"Pangaea was a sort of boomerang shape, and this dinosaur came from its equatorial warm belt, which more or less included northern South America, southern North America and Africa," Langer explained. "To the north and south of this belt, you had big deserts. These findings suggest this area may not have been as barren as before thought, but may have hosted more diversity than the fossil record currently indicates."
The work of Langer and his colleagues was published this week in the online journal Royal Society Open Science.