Can habitat and elevation explain mid-Miocene Neotropical mammal provinciality?

Case Western Reserve University, Cleveland OH

Investigators

Abstract

Non-technical Abstract: Why do so many species live in the tropics? This question can only be answered by uncovering the factors that have affected species diversity over geologic time. A better conceptual understanding of these factors will enable government and conservation organizations to make more informed decisions about how to preserve modern tropical biodiversity. The project will contribute to this effort by generating a detailed picture of the climate and habitats of a 13 million-year-old fossil site in Bolivia known as Quebrada Honda. In addition to producing new scientific insights, the project will have a variety of broader impacts including: increasing participation of Bolivian students and faculty in the sciences; supporting career development of a female PhD candidate; and enhancing Cleveland research infrastructure through new collaborations. Results of the proposed research will be disseminated through a variety of media in English and Spanish including a multimedia exhibit module in the permanent exhibits of the Cleveland Museum of Natural History and an accompanying mobile app on how scientists interpret past climates and habitats. Technical Abstract: Few well-sampled fossil mammal sites are known from the South American tropics. Two of these sites are contemporaneous (late middle Miocene) and widely separated geographically and thus present a unique opportunity to test hypotheses about the de-velopment of South American geographic provinciality. One of these sites, La Venta, Colombia, has been studied in detail. The other site, Quebrada Honda, Bolivia, will be the focus of our fieldwork-intensive project, which will generate new data about deposi-tional environments and habitats of using a variety of geological and paleontological techniques. The main objectives include: (1) stratigraphically correlating the main fossil-producing areas at Quebrada Honda with one another to determine the manner and rate by which fossils accumulated; (2) undertaking detailed studies of ancient soils and trace fossils to reconstruct ancient land surfaces and document past environments; and (3) using ecological characteristics of mammals to deduce the habitats in which they lived. These data will produce a comprehensive picture of the ancient climate and habitats of Quebrada Honda and will be compared to data from La Venta to test whether the great differences in the mammal faunas of these two sites can be explained by differences in paleoenvironment. The observations will also be used test the recent clumped isotope-based assertion that the elevation of Quebrada Honda was more than 2 km when the fossils were deposited.