DISSERTATION RESEARCH: Temporal Patterns in Non-mammalian Synapsid Morphospace

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Non-mammalian synapsids represent the dominant group of terrestrial backboned animals (tetrapods) during the Permian and Early Triassic Periods, 300-245 million years ago. Non-mammalian synapsids have a very rich, temporally well-resolved fossil record by tetrapod standards. This project will use geometric morphometric analysis to study evolutionary patterns in the non-mammalian synapsids. Geometric morphometrics compare the positions of shared features, or landmarks, on specimens (e.g. suture boundaries between bones of the skull) to summarize morphological (shape) variation among individuals. Using a global dataset of non-mammalian synapsid specimens, the researchers will address questions of evolutionary rates and morphological trends associated with the radiation of the group.The period of non-mammalian synapsid dominance was punctuated by the Permo-Triassic extinction, the greatest mass extinction in earth history, in which 95% of all species are estimated to have been lost. The researchers will examine synapsid faunas before and after the extinction to determine whether certain morphologies were preferentially lost, while others survived. These data can be used to identify potentially extinction-prone morphologies in other taxa. Early synapsids are also important because they represent the ancestors of mammals. Studying shape change over the course of synapsid history will provide important information on the evolutionary dynamics underlying mammal origins.