A hole in the historic record of dinosaurs may have just been filled thanks to the finding of a new species that experts are calling a “Frankenstein’s monster.” The odd beast had the looks of the well-known raptor, but unlike that famously flesh-eating creature this new animal was a vegetarian. That makes it potentially a missing link between plant-eaters and theropods like Tyrannosaurus rex and Velociraptor.
Scientists compared around 450 anatomy characteristics of early dinosaurs and placed the new creature, Chilesaurus, in the dinosaur family tree. That suggests it fills a gap between two big dinosaur groups. It may even show how the split took place. Chilesaurus gets its name from the fact it was discovered in Chile. It seems to have lived about 150 million years ago, in the Late Jurassic period, and weird physical characteristics, the researchers say. Chief among those is its flat teeth used for grinding vegetation. Said Matthew Baron, the lead researcher: “Chilesaurus almost looks like it was stitched together from different animals, which is why it baffled everybody.”
Unlike prior research which proposed this dinosaur was part of the so-called “Lizard hips” group known as Therapoda,the new research suggests it came from a different group known as Ornithischia. Ornithischia are sometimes referred to as “bird-hipped” and includes Stegosaurus, Triceratops and Iguanodon.
Chilesaurus shares the bird-hip characteristics of an inverted, bird-like hip structure but does not have the distinctive beak of many other bird-hipped dinosaurs. That makes it a significant find, the researchers say.
Said Baron: “Before this, there were no transitional specimens – we didn’t know what order these characteristics evolved in…. This shows that in bird-hipped dinosaurs, the gut evolved first, and the jaws evolved later – it fills the gap quite nicely.”
Said study co-author Paul Barrett of the Natural History Museum: “Chilesaurus is one of the most puzzling and intriguing dinosaurs ever discovered…. Its weird mix of features places it in a key position in dinosaur evolution and helps to show how some of the really big splits between the major groups might have come about.”
“There was a split in the dinosaur family tree, and the two branches took different evolutionary directions,” said Baron. “This seems to have happened because of change in diet for Chilesaurus. It seems it became more advantageous for some of the meat eating dinosaurs to start eating plants, possibly even out of necessity.”