Posted on behalf of Ashley Yeager
A 190 million-year-old skull could explain when carnivorous dinosaurs moved toward loving their greens. The skull shows that a tiny veggie-dining beast must have eaten some meat too.
“It’s likely that all dinosaurs evolved from carnivorous ancestors,” says Laura Porro, a post-doctoral student at the University of Chicago (press release). “Since heterodontosaurs are among the earliest dinosaurs adapted to eating plants, they may represent a transition phase between meat-eating ancestors and more sophisticated, fully-herbivorous descendents.”
The 4.5 centimetre-long skull belonged to a young Heterodontosaurus and is the world’s second smallest known dinosaur skull. “The skull of a baby dinosaur called Mussasaurus, or mouse lizard, from Argentina is smaller, at only 3 centimetres, [and is] probably the world’s smallest complete dinosaur skull,” Porro told Discovery News.
But even though this new toothy little thing doesn’t take the cake for being the smallest, it could give palaeontologists clues as to how and when dinosaurs, including Heterodontosauri, made the switch from dining on flesh to devouring plants. The creature’s tooth structure –worn, molar-like grinding teeth in the back and fang-like canines at the front – hints that the juvenile and his cousins were “in the midst of that transition”, says Porro, who helped described the new skull in the Journal of Vertebrate Paleontology.
The skull was dug up in the 1960s but never identified. Porro found it in a drawer in the Iziko South African Museum in Cape Town, South Africa, while researching the eating habits of adults of this kind of dinosaur.
Heterodontosauri lived during the Early Jurassic period. The adults reached just over a metre in length and weighed about 2.5 kilograms.
The juvenile most likely weighed less than 200 grams and would have been just about a foot and a half long, with relatively large eyes and a short snout, compared to an adult. “It’s the same things that makes puppies and kittens appealing,” Purro told Reuters, adding that the new little guy is “adorable”.
Image: Natural History Museum