The recent discovery of a 90-million-year-old dinosaur in Patagonia demonstrates that dromaeosaurs, a group of carnivorous theropods that includes Velociraptor and is closely related to birds, originated much earlier than previously thought. Rather than originating during the Cretaceous, dromaeosaurs can now be traced back to the Jurassic, possibly as far back as 180 million years ago. Meanwhile, the new dinosaur's birdlike features--its huge, hollow wishbone; long, winglike forelimbs; and bird-like pelvis--provide more evidence linking dinosaurs to birds.
Buitreraptor gonzalezorum is described in the cover story of Nature October 13. It was excavated last year by a team of Argentine and American paleontologists, including Peter Makovicky, curator of dinosaurs at The Field Museum.
"Buitreraptor is one of those special fossils that tells a bigger story about the Earth's history and the timing of evolutionary events," says Makovicky, lead author of the Nature paper. "It not only provides definitive evidence for a more global distribution and a longer history for dromaeosaurs than was previously known, but also suggests that dromaeosaurs on northern and southern continents took different evolutionary routes after the landmasses they occupied drifted apart."
The paleontological field team was led by Argentine paleontologist Sebastin Apestegua. He and Federico Agnolin, both affiliated with the Museo Argentino de Ciencias Naturales and the Fundacin Flix de Azara, are co-authors of the Nature paper.
"The preservation of Buitreraptor is superb, and the rock layer it comes from represents the oldest interval of the Late Cretaceous," Apestegua says. "The rich fauna of this area, known as La Buitrera, includes other carnivorous dinosaurs, such as mid-sized abelisaurs and the gigantic Giganotosaurus. However, the most common animals are bulky herbivorous sphenodontids, snakes, terr