The “Frankenstein dinosaur” is thought to be the missing link that connects plant-eating species such as the Stegosaurus to a group of carnivorous ones such as the Tyrannosaurus
The mysterious, plant eating dinosaur walked the Earth 150 million years ago and is known as the Chilesaurus. At first, it confused scientists due to its physical characteristics, drawn from two groups of dinosaurs that were thought to be separate.
The Chilesaurus was originally discovered in South America and has the head of a carnivore, but the flat teeth of a plant eater.
“Chilesaurus almost looks like it was stitched together from different animals, which is why it baffled everybody,” said Matthew Baron, a Ph.D. student in the University of Cambridge
The researchers studied more than 450 anatomical characteristics of early dinosaurs to find the right category in which to put the Chilesaurus.
Before, scientists had thought that the Chilesaurus was a good fit to the Theropoda, which is the “lizard-hipped” group that includes Tyrannosaurus. However, latest studies suggest that the dinosaur is in fact a very early member of a group named Ornithischia, a “bird-hipped” group that includes the Stegosaurus and Triceratops.
The Chilesaurus has the inverted hip of the Ornithischia group, which allowed for complex digestive systems. This digestive system led to larger plant-eaters evolving. However, the Chilesaurus did not have the distinctive beak that other dinosaurs classified for Ornithischia have for eating.
“Before this, there were no transitional specimens — we didn’t know what order these characteristics evolved in,” said Baron in a statement. “This shows that in bird-hipped dinosaurs, the gut evolved first, and the jaws evolved later — it fills the gap quite nicely.”