By using CT scanning technology combined with computer simulations, paleontologists have revealed what role keratinous beaks of some dinosaurs played in their life.
Erlikosaurus andrewsi. Image credit: Dinosaur-world.com.
The study, published in the Proceedings of the National Academy of Sciences, is focused on the skull of Erlikosaurus andrewsi, a 4-m-long herbivorous dinosaur called a therizinosaur.
Erlikosaurus lived in what is today Mongolia during Cretaceous, about 90 million years ago. Fossil evidence shows that the snout of this dinosaur was covered by a keratinous beak.
The findings of the new study show that the beak of Erlikosaurus played an important role in stabilizing its skeletal structure during feeding, making the skull less susceptible to bending and deformation.
“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,” said study lead author Dr Stephan Lautenschlager from the University of Bristol, UK.
“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 study co-author Dr Emily Rayfield, also from the University of Bristol.
“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,” said co-author Prof Lawrence Witmer from the Ohio University Heritage College of Osteopathic Medicine.
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Bibliographic information: Stephan Lautenschlager et al. Edentulism, beaks, and biomechanical innovations in the evolution of theropod dinosaurs. PNAS, published online December 2, 2013; doi: 10.1073/pnas.1310711110
