New fossil findings on dinosaur skulls have clued scientists in to the existence and importance of ancient beaks, a facial feature that was previously believed to have evolved later in birds to replace dinosaur teeth, reports.

While it is common knowledge that modern birds have beaks that come in a variety of shapes and sizes, new fossil findings suggest that different groups of dinosaurs during the late Cretaceous Period had them as well, as discovered by an international team of scientists who used "high-resolution X-ray computed tomography (CT scanning) and computer simulations to take a closer look" at the fossilized keratin-covered beaks of the therizinosaur .

For the study, the researchers studied the skull of the therizinosaur (Erlikosaurus andrewsi), an herbivore that grew 10 to 13-feet and lived more than 90 million years ago during the Cretaceous Period in the region today known as Mongolia. Part of its snout was covered in a keratinous beak, which the researchers speculate helped protect the dinosaur's skull from being crushed or bent during feeding, effectively stabilizing its skeleton.

“It has classically been assumed that beaks evolved to replace teeth and thus save weight, as a requirement for the evolution of flight. Our results, however, indicate that keratin beaks were in fact beneficial to enhance the stability of the skull during biting and feeding," Stephan Lautenschlager of Bristol’s School of Earth Sciences told

“Using Finite Element Analysis, a computer modeling technique routinely used in engineering, we were able to deduce very accurately how bite and muscle forces affected the skull of Erlikosaurus during the feeding process. This further allowed us to identify the importance of soft-tissue structures, such as the keratinous beak, which are normally not preserved in fossils,” explained Emily Rayfield, Reader of Palaeobiology at Bristol.

Lawrence Witmer of the Ohio University Heritage College of Osteopathic Medicine, added that beaks evolved several times "during the transitions from dinosaurs to modern birds, usually accompanied by the partial or complete loss of teeth and our study now shows that keratin-covered beaks represent a functional innovation during dinosaur evolution.”

The latest study, led by the University of Bristol, is published in Proceedings of the National Academy of Sciences (PNAS). 

Click here to see photos of the digital reconstructions and models the researchers created of the therizinosaur's keratinous beak.