Collaborative Research: Dinosaur Jaw Muscle Evolution and the Origins of Avian Cranial Kinesis

University Of Southern Indiana, Evansville IN

Investigators

Abstract

Next to feathers and flight, movements between bones of the skull (cranial kinesis) is the most recognizable evolutionary adaptation of birds and a textbook example of musculoskeletal biomechanics used in classrooms worldwide. However, the origins of this innovation remain trapped within the dinosaur-bird fossil record. The researchers supported by this award will explore the biomechanical evolution of the avian head using 3D anatomical and computational modeling of fossil and living dinosaurs. This project will create interdisciplinary collaborations of paleontologists, comparative biomechanists and engineers. 3D models, discoveries and other data will be used to train K-12 students and teachers in mid-Missouri as well as young investigators in comparative biomechanics and avian evolution. This project integrates anatomy, biomechanics, paleobiology, engineering, and computer science and will train a postdoctoral researcher, graduate, and undergraduate students through REU support and summer internships. Mid-Missourian and Appalachian teachers will be trained in STEM topics related to avian anatomy, biomechanics and evolution through immersive, embedded lab internships and workshops through the Inside Dinosaurs experience at University of Missouri and the Visible Interactive Dinosaur (VID) at Ohio University. Public outreach will occur through Missouri's Dinosaurs & Cavemen science exposition and VID avenues. 3D models of skulls and muscles will be made available as interactive web modules for education and research. Cranial kinesis among archosaurs is a classic example of a key innovation in vertebrate evolution, resulting in enhanced cranial dexterity, extreme dietary flexibility, and the subsequent adaptive radiations of crown-clade birds. During the evolutionary transition from dinosaurs to birds, jaw muscles shifted positions, bony connections were lost, and intracranial joints became increasingly flexible. Studies supported by this award will analyze the evolution of jaw muscle forces within the cranium of non-avian and avian dinosaurs using novel 3D computational methods. These findings will allow the estimation of intracranial joint loading during feeding in extinct taxa and explore the evolution of individual jaw muscles in cranial function. The results will be integrated with neuroanatomical data to uncover the coevolutionary relationships between the brain and feeding apparatus. New 3D models of the dinosaur feeding apparatus will provide the template for numerous future studies of cranial functional morphology in other vertebrates. This work will complement and provide the necessary foundation for multi-body dynamic models of vertebrate feeding, will provide guidance for material properties testing and XROMM analysis, chondral modeling of cranial skeletal tissues, and will develop 3D datasets that can be used to test patterns of cranial modularity and skull function. Results from the studies will be presented at scientific meetings and published in peer-reviewed journals.