December 3, 2013
Beaks Were Functionally Important In Protecting Dinosaur Skulls
April Flowers for redOrbit.com - Your Universe Online
One typical hallmark of modern birds that comes in a huge variety of shapes and sizes is the beak. While this is common knowledge, it is less well known that during the Cretaceous Period keratin-covered beaks had already evolved in different groups of dinosaurs.
A international team of scientists, composed of Dr Stephan Lautenschlager and Dr Emily Rayfield of the University of Bristol with Dr Perle Altangerel of the National University of Mongolia in Ulaanbaatar and Professor Lawrence Witmer of Ohio University, used high-resolution X-ray computed tomography (CT scanning) and computer simulations to take a closer look at these dinosaur beaks.
The researchers focused on the skull of Erlikosaurus andrewsi, which was a 10- to 13-foot-tall herbivore dinosaur called a therizinosaur. E. andrewsi lived more than 90 million years ago during the Cretaceous Period in the region now known as Mongolia.
The findings, published in Proceedings of the National Academy of Sciences (PNAS), show evidence that part of the snout of this dinosaur was covered by a keratinous beak. Further, they reveal that keratinous beaks played an important role in stabilizing the skeletal structure during feeding, making the skull less susceptible to bending and deformation.
Dr Stephan Lautenschlager of Bristol's School of Earth Sciences said, "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."
"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," added Dr Emily Rayfield, Reader of Palaeobiology at Bristol.
Lawrence Witmer, Chang Professor of Paleontology at the Ohio University Heritage College of Osteopathic Medicine noted, "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."