The Gray Fossil Site in northeastern Tennessee preserves materials from a 5-million-year-old ecosystem, including wood from nearby trees. Trees provide a unique perspective into ecosystems as they are immobile during their lifetime. As such, tree rings convey information about precipitation and temperature for a given location. As southern Appalachia is one of North America’s most biodiverse regions, and modern climates are warming, understanding the warmer past climate of the Gray Fossil Site can help predict the region’s future. This study consists of three parts: conservation of wood remains, identification of taxonomic groups represented by the fossil wood, and the measured organic content of fossil wood from the Gray Fossil Site. When excavated, the wood is saturated due to a modern local high water table. A variety of drying methods from paleontology, archaeology, and dendrology were compared on saturated samples, from string wrapping to refrigeration, alcohol replacement to microwaving. The method least likely to cause warping and cracking is to wrap specimens in cotton string to slow drying. Microscopic examination of the wood reveals tree rings that have identifying features. Utilizing identification keys for tree rings, each specimen with visible rings can be identified. Taxa represented by fossil wood specimens are like those present in pre-modern forests. Finally, loss on ignition tests reveal that the Gray Fossil Site wood lacks extensive permineralization or mineral replacement. As the wood is 80-90% organic, alpha-cellulose can be extracted. The presence of alpha-cellulose, albeit stained with iron oxides, indicates that future stable isotope analyses are possible.

A thorough morphological description of Teleoceras material from the Gray Fossil Site, Gray, Tennessee is provided. This is the only record of a browsing Teleoceras and, as a late Hemphillian locality, represents one of the youngest populations. Linear measurements of post-cranial elements indicate proportional differences between Teleoceras from the Gray Fossil Site and those from other Hemphillian localities. These differences are more pronounced in the elements of the forelimb than in those of the hind limb. Statistical analyses of post-cranial elements from 3 Hemphillian species of Teleoceras suggest that these differences should not be used to separate species. However, the elements do typically sort well by fossil locality, which suggests that post-cranial morphology is plastic enough to become modified within a population. Furthermore, dental morphology comparisons with the holotypes of these species indicate that the GFS rhino represents a previously undescribed species.

Researchers at the GFS, Washington County, Tennessee through the wet screening of nearly 100%of the sediment excavated at the site, recovered an extensive collection of anuran fossil elements. Until recently, these specimens have not been analyzed. The purpose here is the examination, description, and identification of all non-ranid anuran (frogsand toads) material using the following elements: ilium, urostyle, maxilla, frontoparietal, and last sacral vertebra. Anurans identified include Scaphiopus wardorum(extinct spadefoot toad), Bufo terrestris(southern toad), B. cf. B. marinus(giant neotropical toad), three morphotypes of Hyla(tree frogs), and Pseudacris cf. P. brachyphona(mountain chorus frog). Occurrence of these Anura support a paleoecological environment described as warm, moist, and wooded.

Due in part to the incompleteness of the Cenozoic fossil record in the eastern U.S., the evolution and immigration of shrews (Soricidae) is not well understood. A rich soricid fauna from the Gray Fossil Site (GFS), Washington County, TN, has enabled many new inferences to be made. There are 7 new species in 6 genera: Paenelimnoecus, “Blarinella”, Petenyia, Tregosorex, Crusafontina, and Gen et sp. nov. GFS species of the genera Paenelimnoecus, “Blarinella”, and Petenyia are the first occurrence of each genus in the New World. Tregosorex, Crusafontina, and the N.A. taxon Limnoecus all have their latest documented occurrence at the GFS, extending their temporal range by at least 1 million years. “Blarinella” sp. nov. has a complete lateral groove in the inferior incisor, providing the earliest evidence for venom in soricids by at least 4 million years. GFS taxa also provide insight into the evolution of both Soricini and Blarinini.

Thesis (Ph.D.)--Baylor University, 2009. / Includes bibliographical references (p. 88-96).

The Gray Fossil Site in northeastern Tennessee preserves materials from a 5-million-year-old ecosystem, including wood from nearby trees. When excavated, the wood is saturated due to a modern local high water table. Moisture in the wood prevents further dendroecological research, which would provide important, annual-scale climate information from tree rings visible in the wood. In order to analyze climate-sensitive wood variables, wood samples must be dried with minimal cracking prior to further research. To test the best method for drying wood samples, a variety of methods were studied. Cotton string, wrapped firmly around a sample, and a sandbox, comprised of a sample surrounded equally on all sides by sand within a five gallon container, were both be used to test the effects of minimizing expansion and contraction during drying. A vacuum oven, a microwave, and a refrigerator were used to monitor the rate at which the wood dries under different temperature conditions, and a control sample was dried in a fume hood as a comparison. An alcohol replacement test provided data on the rate of non-water evaporation. Drying methods were evaluated by measuring the drying speed of each sample and the degree of visible surface cracking. Of the methods tested, wrapping wood samples in cotton string at an even pressure, then allowing the sample to dry in a fume hood is the best practice for drying the wood from the Gray Fossil Site. The string resulted in the least cracking, and one of the shorter drying times without destroying the sample, as the vacuum oven and microwave tests did. This work not only provides a comparison of standard drying methods for saturated fossils of the non-wood varieties, but lays the groundwork for further studies examining the wood, tree rings, and climate at the Gray Fossil Site.

Endocranial morphology provides evidence of sensory ecology and sociality of extinct vertebrates. The Earliest Pliocene Gray Fossil Site (GFS) of NE Tennessee features a conspicuous dominance of skeletal elements belonging to the dwarf tapir, Tapirus polkensis. Numerous individuals in one fossil locality often suggests gregarious behavior, but sociality in T. polkensis contradicts behavior documented for extant Tapirus species. I test T. polkensis for variation in sensory and social ecology using computed tomography and 3D digital endocasts from an ontogenetic sequence. I compare the T. polkensis endocasts with extant Tapirus species using Encephalization Quotients (EQs) and 3D geometric morphometrics. Results show conserved endocast morphology for Tapirus, and thus, conserved sensory and social ecology. Tapirus behavior is likely consistent for ~5 Ma, and extant Tapirus behavior can be inferred for T. polkensis. The large number of individuals from the GFS is likely the result of a preservation bias unrelated to gregariousness.

The Gray Fossil Site in northeastern Tennessee preserves materials from a 5-million-year-old ecosystem, including wood from nearby trees. This study consists of three parts: conservation of wood remains, identification of taxonomic groups represented by the fossil wood, and measuring the organic content of fossil wood from the Gray Fossil Site. When excavated, wood specimens from the site are saturated due to a high local water table. After testing seven different techniques to dry wood specimens, wrapping a specimen in string and allowing it to dry slowly was the method least likely to cause warping and cracking. Microscopic examination of wood cross sections reveal tree rings with distinct anatomical features, with implications for taxonomic identification. Tentatively identified taxa that are present at the Gray Fossil Site are similar to those present in pre-modern forests of northeastern Tennessee. Finally, loss on ignition tests indicate that the Gray Fossil Site wood lacks extensive permineralization or mineral replacement. The presence of alpha-cellulose, albeit stained with iron oxides, illustrates the potential for future stable isotope analyses.

Fossil fruits including nuts and associated husk valves of a new species of Carya (Juglandaceae) are described from the latest Miocene to earliest Pliocene in northeastern Tennessee, eastern United States. The husk valves are elliptic, 1.2-4.5mm thick, with a convex exterior face and a concave interior face; the nuts are globose to ovoid in shape, smooth and longitudinally ribbed on exterior surface, with a short protruding apex and a slightly 4-angled base; inner ribs, lacunae and primary septa are well-developed, while secondary septa are absent or weakly developed. The combination of these carpological characteristics clearly shows a close resemblance to the genus Carya in Juglandaceae. Detailed comparisons of carpological morphology and anatomy indicate that the present fossil taxon is different from both living and most other fossil species of the genus, and therefore warrants the designation of a new fossil species, Carya tennesseensis Huang et al., sp. nov. Carya tennesseensis displays a carpological similarity to C. ventricosa from the late Oligocene to early Pliocene in Europe, suggesting a potential species exchange of the genus between Europe and southeastern North America during the late Neogene. The new fossil species represents one of the few fruit fossil species of Carya from its modern distribution range in southeastern North America. It provides crucial information for better understanding the rapid diversification of the genus from the late Miocene to early Pliocene, and the origin and establishment of today's Carya biodiversity in this region.

This study focuses on morphometric and systematic analyses of the fossil Vitis seeds, recovered from the Gray Fossil Site (7-4.5. Ma, latest Miocene-earliest Pliocene), northeastern Tennessee, U.S.A. A multivariate analysis based on eleven measured characters from 76 complete fossil seeds recognizes three morphotaxa. Further comparisons with both selected modern and fossil vitaceous specimens confirm that these morphotaxa represent three new species, viz. Vitis grayensis sp. nov., Vitis lanatoides sp. nov., and Vitis latisulcata sp. nov. Furthermore, the close resemblance of the first two fossil grapes (V. grayensis and V. lanatoides) with two East Asian Vitis species provides further support concerning a strong eastern Asian aspect of the Gray fossil biota in the late Neogene southeastern North America, as previously evidenced by both animals (e.g. Pristinailurus bristoli [red panda]) and other plants (e.g. Sinomenium and Sargentodoxa).