Computed Tomography of Endocranial Morphology in Fossil Cetaceans

Emory University, Atlanta GA

Investigators

Abstract

Abstract for NSF 0087698 Computed Tomography of Endocranial Morphology in Fossil Cetacea Lori Marino, Principal Investigator/Project Director Mark D. Uhen, Co - Principal Investigator The origin and evolutionary history of Cetacea (dolphins, whales, and porpoises) represents one of the most dramatic transformations in the fossil record. Some of the most significant changes that occurred throughout cetacean evolution were in the relative size and organization of the brain. Yet, relatively little is currently known, in any detailed systematic way, about brain evolution in cetaceans. Skeletal fossils document the major evolutionary changes in cranial and post-cranial morphology that occurred. The purpose of this project is to use Computed Tomography scanning technology to image and measure endocranial morphology of eighty-five fossil cetacean specimens, spanning the mid-Eocene to the present, from the Department of Paleobiology at The Smithsonian Institution. Specifically, the objectives of this study are to: 1) measure and document endocranial volume and morphology, along with postcranial indicators of body mass, in individual fossil and modern cetacean specimens, 2) use these data to estimate encephalization level and changes in brain structure in fossil and modern taxa, 3) reconstruct the sequence of changes in brain size and morphology in cetaceans within a phylogenetic context, and 4) test specific hypotheses about brain evolution in cetaceans. This project will provide the first testable database on cetacean brain evolution. In addition, these data also have the potential to inform broader comparative questions about mammalian brain evolution.