article_snippet.sent: A new lineage of dinosaur that grazed on plants, despite being closely related to notorious carnivore Tyrannosaurus rex, has been discovered in Chile.
article_snippet.sent: The animal is proving to be an evolutionary jigsaw puzzle because The animal belongs to the theropod group of dinosaurs - which were predominantly carnivorous and included the famous meat eaters Velociraptor, Carnotaurus and Tyrannosaurus, from which birds today evolved - but was a vegetarian.
article_snippet.sent: The presence of herbivorous theropods was up until now only known in close relatives of birds, but Chilesaurus shows  a meat-free diet was acquired much earlier than first thought.
article_snippet.sent: carnivorous dinosaurs known as the therapods - which includes Tyranosaurus rex and velociraptor are thought to have been the ancestors of modern birds.
article_snippet.sent: Birds are descended from dinosaurs, but how exactly the transition occurred is not really clear.
article_snippet.sent: There are three main groups of flying vertebrates - the birds, which evolved from dinosaurs, pterosaurs that were flying reptiles that existed alongside the dinosarus, and the bats, which are mammals that evolved after the extinction of the dinosaurs 66 million years ago.
article_snippet.sent: It is likely that the conclusions will be controversial with other evolutionary biologists, but the conclusions could prove hugely valuable in unravelling how birds evolved from birds dinosaur ancestors.