Meeting Abstract

P3.146  Thursday, Jan. 6  The Nose Knows: Modeling Airflow in Alligators and Dinosaurs BOURKE, J.B.*; WITMER, L.M.; Ohio University; Ohio University College of Osteopathic Medicine jb513009@ohio.edu

The presence and function of respiratory turbinates (RTs) in dinosaur physiology have been contentious. The function of RTs in the nasal passage ultimately relies on knowledge of how air flows throughout this region. To date, airflow studies have been limited to mammals, where complicated RTs have made modeling difficult. The nasal passages of extant reptiles are generally simpler than mammalian or avian ones due in large part to a lack of complicated turbinates. Constructing accurate models of these simpler passages provides a foundational view of how nasal architecture affects airflow. CT scans of the nasal passages of American alligators (Alligator mississippiensis) were converted in Avizo into 3D models that underwent computational fluid dynamic analysis in Fluent. Results uncovered distinct heterogeneity in airflow throughout the nasal cavity. High-velocity, laminar flow characterized most of the respiratory portions of the nasal passage whereas slower, more stagnant air was located in the olfactory region. These findings agree with mammalian studies showing a disparity in airflow velocities between the respiratory and olfactory regions. Our study presents the first time that airflow in the nasal passage of an extant reptile has been modeled. Future studies will incorporate models of respiratory airflow in birds and squamates. Accurate knowledge of how various anatomical components (e.g., turbinates) affect airflow patterns in extant taxa will allow tests of hypotheses of nasal airflow and respiratory physiology in dinosaurs. To this end, a preliminary, proof-of-concept restoration of nasal airflow in the Cretaceous theropod Majungasaurus also revealed disparity in respiratory and olfactory airflow speeds.