T. rex had a weird vegetarian relative, say scientists
A relative of聽Tyrannosaurus rex聽didn't share the infamous carnivore's appetite for meat, a new study finds. Instead, the newly discovered 9.8-foot-long (3 meters) dinosaur munched on plants about 145 million years ago during the Late Jurassic period.
The new species is a member of the theropod group, which consists of mostly carnivorous dinosaurs and includes not only聽聽but also the fearsome聽. The newfound "bizarre herbivorous" creature looked like a mixture of a plant-grazing, long-necked sauropodomorph; an herbivorous beaked ornithischian; and a meat-eating theropod, the study researchers said.
"When I saw all the fragmented bones laying on the table, I thought all of them belonged to different dinosaur lineages," said the study's lead researcher, Fernando Novas, a researcher at the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires, Argentina. "That dinosaur is spectacular and bizarre because it combines different features belonging to these three main groups of dinosaurs." []
Researchers uncovered the curious fossils in 2010. The observant 7-year-old son of two geologists spotted a few dinosaur vertebrae during an expedition with his family in Ays茅n, a region in southern Chile. The researchers named the new dinosaur聽Chilesaurus diegosuarezi, in honor of Chile and the boy, Diego Su谩rez.
Since Diego's discovery, collaborating Chilean and Argentinian scientists have uncovered more than a dozen聽Chilesaurus聽specimens, including four complete skeletons ranging from the size of a turkey to almost 10 feet (3 m) long.
If they had not discovered the complete specimens, researchers may have identified different parts of聽Chilesaurus聽as belonging to different species, the scientists said. For instance, the dinosaur's ilium, the upper, large part of the pelvic bone, looks like that of a theropod. It also had robust forelimbs and likely walked on its hind legs, like other theropods, Novas said. However,听Chilesaurus聽did not have sharp claws like聽Velociraptor, but instead sported two blunt fingers for hands.
Chilesaurus聽also had a small skull, long neck and large, clunky feet reminiscent of a聽, Novas said. "In the case of聽Chilesaurus, its legs were more adapted to walk, not to run," he said. "The hind foot is composed of four well-developed toes, different from the three-toed feet of a theropod."
惭辞谤别辞惫别谤,听Chilesaurus聽had a pubic bone that looks like that of an ornithischian, Novas said. It's possible that the pubic bone rotated backward over evolutionary time to allow聽Chilesaurus聽more room in its gut to digest plant material, the researchers said.
The new species is a "wonderful weirdo," said Thomas Carr, an associate professor of biology at Carthage College in Wisconsin and a vertebrate paleontologist, who was not involved in the study.
"We're learning about the rules of聽," Carr told Live Science. "It shows that the dinosaurs across theropods and sauropodomorphs and even ornithischians tend to follow the same rules in changing their bodies," when they evolved into herbivores.
Chilesaurus聽isn't the only herbivorous theropod. The therizinosauroidae, which lived in present-day Asia and North America, also ate plants.
Therizinosauroidae "also have relatively small heads and long necks and stumpy feet," Carr said. "And their hip bones and pubis point backward. And these [features] are broadly similar to聽Chilesaurus."
The remarkable fossils "say something about the limits upon dinosaur evolution," Carr said. "It just shows that we really don't know much about dinosaurs at all."
The study was published online today (April 27) in the journal聽.
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