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Smith Lecture: Fossils, Isotopes, and Rainforests: New Approaches Challenge Foundational Tenets of Stable Isotope Terrestrial Paleoecology and Biogeographical Reconstructions of Mammals in the Neotropics

Julia Tejada, Université de Montpellier
Friday, January 29, 2021
1:30-2:30 PM
Zoom ID# 923 5747 7753
Stable isotope analyses are powerful tools for reconstructing ancient ecologies and ecosystems, as they are independent of morphology and reflect dietary ecology. The application of stable isotope analyses, however, is not without limitations, as determination of food web dynamics using these methods often relies on poorly tested assumptions. On the other hand, estimation of geographic ranges of extinct organisms is usually addressed through biological and geological proxies separately leading many times to conflicting results. The structure of this talk is twofold. First, I will show my work testing some foundational cornerstones on which stable isotope ecology methods rely, in order to validate the suitability of applying these techniques to different mammalian clades, and to more reliably interpret the isotopic signals preserved in extinct organisms. Specifically, I will show the lack of validity of an important assumption behind the interpretation of stable carbon isotope analyses for understanding diets in terrestrial mammalian herbivores. Furthermore, the results of my studies on Amazonian mammals challenge the existing paradigm governing identification of closed canopy rainforests in the fossil record using mammalian d13C data. Second, using fossil sloths as a case study, I will show my ongoing research trying to reconcile Caribbean paleogeography with the evolutionary history of sloths and other mammals in the region. This new phylogeny time-stratified-based approach aims to explain the origin and colonization routes of sloths in the Caribbean and the potential role of abiotic variables (e.g., land area over time) in the diversification dynamics of this group of mammals.
Building: Off Campus Location
Location: Virtual
Event Link:
Event Type: Lecture / Discussion
Tags: Lecture
Source: Happening @ Michigan from Earth and Environmental Sciences