EAGER: Neogene fruits and seeds from the Gray Fossil Site, Tennessee: Using multiple imaging techniques to clarify an obscure interval in the history of Appalachian vegetation

Paleontological Research Institute, Ithaca NY

Investigators

Abstract

This project will analyze the fossilized fruits and seeds from the Gray Fossil Site located in eastern Tennessee. Ongoing excavation of the site, an ancient sinkhole deposit discovered in 2000, has yielded numerous, well-preserved fossils of terrestrial plants and animals that lived approximately seven to four-and-a-half million years ago. The vegetation of this time period in the Appalachian region is significant because it predates the widespread ecological disturbance caused by Pleistocene-age environmental changes, yet its biodiversity is not well understood. Consequently, the Gray Fossil Site presents a unique opportunity to clarify how ecosystems of the Appalachian region have changed over recent geological history. Researchers will identify species of fossil fruits and seeds from the site and will describe those new to science. They will then compare the diversity of fossil plant species found at the site to that of other ancient and modern plants world-wide. The comparison may provide transformative insights regarding the pace of biological diversification, extinction, and geographic range shifts of plant species at a local to global scale. Researchers will train undergraduate students and engage the public at the Gray Fossil Site and Museum by producing a digital visitor's guide to the fossil flora. Research results will be disseminated widely and will include contributions to the NSF-funded, open access Digital Atlas of Ancient Life. This project will create the first comprehensive carpoflora for the Gray Fossil Site. Researchers will analyze previously excavated fruit and seed fossils using a combination of light microscopy, scanning electron microscopy and micro-computed tomography. These methods supply complementary data that characterize both surface morphological and internal anatomical details without the need for destructive dissection. Project personnel will determine the systematic affinities of the fossils using structural characteristics and phylogenetic analyses, where feasible. They will then assess the biogeographic relationships of the carpoflora based on the taxonomy of the fossils. These data will test the hypothesis that the carpoflora will share greatest similarities to the ancient and modern floras of Eurasia and North America. Outcomes of this project will include an improved understanding of Miocene and Pliocene ecosystems of North America, the historical biogeography of the Appalachian flora, and the state of internal anatomical preservation of the Gray Fossil Site carpoflora. The project will improve the curation of US fossil collections and strengthen research collaborations among US institutions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.