Cricetidae, which includes a wide range of mice and rats, is the second-most diverse and abundant family of mammals. Though presently distributed across the Americas and Eurasia and also known from many fossil sites in western North America, few records have been studied from the east prior to the Pleistocene. This study has identified seven species of cricetids from the Gray Fossil Site (GFS), an early Pliocene site located in the northeast corner of Tennessee well-known for preserving fossils of many large mammals. While a few studies had previously noted the occurrence of cricetids at GFS, this study provides a detailed description of the cricetid assemblage and helps expand our understanding of small mammals from this site. Specimens were examined under stereomicroscope and DinoLite digital microscope camera, allowing qualitative assessment of occlusal morphology and quantitative comparison to modern cricetids and published fossil records from across North America. The most common taxa at the site included the deer mouse Peromyscus, which is currently the most abundant and widely distributed mammal in North America, deer mouse-like Postcopemys, and the woodrat Neotoma, which is larger rat with high-crowned molars that still lives in the region today. Other less common ones, like Sigmodon, Repomys, and Neotomodon, are also present. While most of the GFS specimens can be categorized into known genera, distinctive morphological features suggest the presence of new species. This assemblage of cricetids differs from those found at contemporaneous sites, emphasizing the spatial and temporal uniqueness of GFS. The Pliocene cricetid taxa at GFS exhibit diverse body sizes and dietary preferences, providing insights into the paleoecology of the region. As a biodiversity hotspot in the Appalachian region today, GFS was likely an important habitat for cricetid evolution during the Pliocene.

The Gray Fossil Site (GFS), a Mio-Pliocene (4.5–7 Ma) locality in the southern Appalachians, boasts the most diverse pre-Pleistocene salamander fauna in North America: Desmognathus sp., Plethodon sp., Notophthalmus sp., a Spelerpinae-type plethodontid, and Ambystoma sp. Because greater taxonomic resolution can result in more precise paleobiological interpretations, additional specimens were studied here. ETMNH 8045, a nearly complete articulated ambystomatid, appears most like Ambystoma maculatum in dentition and vertebral proportions. ETMNH 18219, an isolated vomer, is consistent with modern Pseudotriton and Gyrinophilus in possessing a postdentigerous process and a similar dentigerous row morphology. If these taxa, or species of similar ecological preferences, occurred around the GFS, it seems unlikely they co-inhabited the sinkhole lake. Aquatic stages of Pseudotriton and terrestrial Gyrinophilus last multiple years; their presence could further support a perennial lake interpretation. Modern A. maculatum preferentially breed in vernal pools; confirmed identification could suggest local seasonal wetlands.

Sciurids are one of the most diverse mammalian groups today, but the fossil record does not reflect that diversity. The purpose of this project was to identify sciurids from two late Miocene sites—the Gray Fossil Site (GFS) of Tennessee, and Tyner Farm of Florida—and use those identifications to infer the ecology of the two. From the GFS four sciurids were identified: Eutamias or Neotamias, Glaucomys, and two tree squirrels (Sciurini). Two sciurids were identified from Tyner Farm: a chipmunk attributed to Tamiina, and a ground squirrel attributed to Marmotina. Paleoenvironmental inferences based on the sciurids present at both sites are consistent with previous work. The GFS Eutamias or Neotamias is the first record of a western chipmunk population in eastern North America; the GFS tree squirrels are the earliest record of a tree squirrel in eastern North America. The GFS Glaucomys is the earliest record of the genus.

The Gray Fossil Site is a rich Hemphillian (North American Land Mammal Age) locality located in northeastern Tennessee which has produced tens-of-thousands of fossils of multiple taxa including hundreds of individual snake skeletal remains. Analyzed here are cranial and vertebral fossils identified as belonging to various colubrid taxa including Carphophis sp., Gyalopion sp., Heterodon sp., Natricinae indeterminate, Thamnophis sp., and a new, undescribed genus and species. In addition, multiple new features of snake vertebrae are described, some of which question the validity of the genus Neonatrix. Finally, the distribution and paleoecology of the listed genera allows an interpretation of how snake biogeography have transformed in the southern Appalachians since the Hemphillian.

Analysis of the Gray Fossil Site peccary material indicates the presence of up to three species. Comparisons with the tayassuid material known from the Tyner Farm and Bone Valley Formation of Florida allows the identification of Mylohyus elmorei and at the GFS. Within the GFS material, Prosthennops cf. P. serus and cf. Catagonus sp. are also tentatively recognized but further verification is required. The known range for Prosthennops is expanded into the Appalachian region. Presence of M. elmorei at the Gray Fossil Site provides the first known occurrence of this species outside of the Palmetto fauna of Florida, indicating that the species once exhibited a larger range within the southeastern United States than previously known. Overall, the presence of M. elmorei.indicates another parallel to the Palmetto Fauna of the Bone Valley Formation whereas Prosthennops cf. P. serus may indicate a connection to the Hemphillian of the western United States.

The Gray Fossil Site (GFS) is one of the richest Cenozoic terrestrial localities in the eastern United States. This study describes the first talpid specimens recovered from the GFS. Using measurements and comparisons of dental and humerus morphology, I identify 4 talpids (Parascalops nov. sp., Quyania cf. Q. europaea, Mioscalops (= Scalopoides) sp., and an unidentified stem desman) occurring at the GFS. Humeral morphology has been used to diagnose talpid species and study relationships. A geometric morphometric analysis showed that humerus shape is highly reflective of locomotor ecology in extant talpids and allows ecological inferences for fossil talpids. Hierarchical cluster analysis using morphometric data allowed examination of similarity among taxa and helped to secondarily verify taxonomic designations for the GFS taxa. The resulting phenogram showed strong similarity to the most up-to-date molecular cladogram and actually matched phylogenetic relationships substantially better than any morphological cladistic analyses to date.

A detailed morphological description of a proboscidean manus from the Gray Fossil Site (GFS), Gray, Tennessee is provided. Manus elements from an American mastodon (Mammut americanum), a Britt’s shovel-tusker (Amebelodon britti), an undescribed small gomphothere species, and a Columbian mammoth (Mammuthus columbi) are used for comparisons. Linear measurements indicate proportional differences between the GFS mastodon and other proboscidean taxa ranging from the Hemphillian to Rancholabrean land mammal ages. Possible pathologies are also described. The purpose of this study is to determine how the GFS mastodon differs in manus morphology and locomotion from different proboscidean taxa, including size, environmental, evolutionary, and taxonomic factors. Morphological differences are more pronounced in carpals and metacarpals in regard to shape, size, and orientation of articular surfaces but are not statistically compared due to the small sample size.

A second nearly complete skeleton of the fossil ailurid Pristinailurus bristoli was recently recovered from the Hemphillian (late Miocene) Gray Fossil Site of northeast Tennessee. It appears to be significantly larger than the previously known skeleton of P. bristoli, which was surprising as the living red panda Ailurus fulgens is thought to be generally monomorphic, including between sexes. Here the presence of significant size difference in the geometric means of cranial and postcranial measurements and canine area in the two specimens of P. bristoli is tested relative to the distribution of size differences in intersex and intrasex pairs of A. fulgens. The presence of sexual dimorphism in these dimensions is also assessed in A. fulgens using t-tests. We report the first evidence of sexual dimorphism in both upper and lower canine area in A. fulgens. We also found evidence of significantly greater body size difference in the two specimens of P. bristoli than that present in A. fulgens. This could reflect a variety of causes, including the presence of multiple species or subspecies, a greater range of ecologically driven variability, or the presence of sexual dimorphism. We argue tentatively for sexual dimorphism as the most plausible explanation for the apparent size range of P. bristoli.

The occurrences of Staphylea L. (Staphyleaceae) fossils have been abundantly documented from the Cenozoic of Eurasia, but none has been confirmed from North America to date. In this study, we describe Staphylealevisemia sp. nov. on the basis of seed remains from the latest Miocene to earliest Pliocene of northeastern Tennessee, southeastern USA. The seeds are characterized by a smoothly inflated body, a large hilar scar perforated by several vascular traces and bordered by a distinctive lip-like rim, a cuticle coating the seed coat interior, and seed coat section containing weakly developed tiny lumina. According to the paleogeographic distribution of the genus, it is hypothesized that Staphylea originated from western Eurasia no later than the late Oligocene, and arrived in eastern North America no later than the late Neogene, most possibly through the North Atlantic land bridges like many other seed plants.

The Gray Fossil Site (GFS) of northeastern Tennessee has yielded a diverse salamander fossil assemblage for the southern Appalachian Mio-Pliocene. This assemblage includes at least five taxa (Ambsytoma sp.; Plethodon sp., Spelerpinae, gen. et sp. indet., Desmognathus sp.; and Notophthalmus sp.) from three families (Ambystomatidae, Plethodontidae, and Salamandridae, respectively). All taxa are present in the area today and support a woodland-pond interpretation of the site. Reported specimens represent the earliest record of their families in the Appalachian Mountains (and the earliest record of Plethodontidae and Ambystomatidae east of the Mississippi River); with the Notophthalmus sp. vertebrae being the only Mio-Pliocene body fossil known for the Salamandridae in North America. The Desmognathus sp. specimens may help shed light on the evolutionary origins of the genus Desmognathus, which purportedly has its roots in this region during the Mio-Pliocene.