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.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:asrf-2100 |
| Date | 25 April 2023 |
| Creators | Xu, Ziqi, Samuels, Joshua X. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | Appalachian Student Research Forum |
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