For this study, which will appear in the June 2005 issue of The American Naturalist, researchers collected more than 4000 specimens of fossil leaves, fruits, seeds, and flowers at a site with outstanding fossil preservation, Laguna del Hunco. Adjusted for sampling effort, the Laguna del Hunco flora, which has produced 186 species, is more diverse than any comparable deposit known elsewhere in the world. Preliminary collections at a second site, Río Pichileufú, show comparable richness. Precise radioisotopic ages, including the first from the Río Pichileufú flora, show it be almost 5 million years younger (47.46 ± 0.05 myr) than Laguna del Hunco (51.91 ± 0.22 myr). Highly diverse floras were present in a warm area of South America by the Eocene and were long lived and areally extensive.
Sponsored by the American Society of Naturalists, The American Naturalist is a leading journal in the fields of ecology and evolutionary biology and animal behavior. For more information, please see our website: http://www.journals.uchicago.edu/AN
Peter Wilf (Pennsylvania State University), Kirk R. Johnson (Denver Museum of Nature and Science), N. Rubén Cúneo (Museo Paleontológico Egidio Feruglio, Argentina), M. Elliot Smith (University of Wisconsin), Bradley S. Singer (University of Wisconsin), and Maria A. Gandolfo (Cornell University), "Eocene plant diversity at Laguna del Hunco and Río Pichileufú, Patagonia, Argentina"165:6 June 2005.