Collaborative Research: Andean Fossil Mammals--Phylogenetic and Geologic Implications

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Collaborative Research: Andean Fossil Mammals-Phylogenetic and Geologic Implications.A grant has been awarded to Dr. John J. Flynn of the Field Museum of Natural History and Dr. Darin A. Croft of the University of Chicago to collect and study fossil mammals from the Andes Mountains of central Chile, and to carry out geological investigations of the region. This study will clarify poorly known aspects of South American mammal evolution, and help unravel the complex geologic history of the Andean mountain chain. Field collecting and reconnaissance will be undertaken to discover new localities and assemblages of fossil mammals of different ages. Once prepared, these fossils will be described in the scientific literature and analyzed in order to understand how factors such as climate change affect species diversity. The unusual occurrence of these fossils in volcanic rocks will enable the application of various "absolute" geologic dating methods, providing precise ages for these fossils and more accurate scientific analyses.South America was an isolated continent for most of the last 80 million years. The highly peculiar mammals arising in response to this isolation have captured the interest of biologists and paleontologists for more than two centuries. Some 15 years ago Dr. Flynn and his colleagues unexpectedly discovered the first fossil mammals from this region of South America. By studying the fossil mammals, the team showed that the fossil-containing rocks were nearly 100 million years younger than previously assumed. This discovery has revolutionized understanding of the region's tectonic history. Moreover, this and other discoveries have helped to fill in important "missing chapters" in South American Mammal history, leading, for example, to the recent recognition of a new South American Land Mammal Age and evidence of the world's oldest grasslands. This project builds on earlier work, focusing on targeted geographic areas and particular groups of mammals (rodents, extinct plant eating forms, marsupials, etc.).