In Tennessee’s Gray Fossil Site, paleontologists have found fossils of an ancient deer, Eocoileus gentryorum, dating to the early pliocene, approximately 5 million years ago. This is the first pre-Pleistocene deer ever found in the Appalachian Highlands and one of the oldest caved-in records of deer in North America.
A paper published by Dr. Joshua X. Samuels et al in Palaeontologia Electronica earlier this month reports these findings. The fossils include a partial skull, an upper molar, and several limb bones of Eocoileus gentryorum.
Humerus of Eocoileus gentryorum (ETMNH 10559) from the Gray Fossil Site, TN in anterior view, along with a comparative sample of fossil cervids. A) ETMNH 10559 Eocoileus gentryorum distal right humerus; B) UF 134788 Eocoileus gentryorum distal right humerus; C) USNM 299483 Odocoileus brachyodontus distal right humerus; D) UF 239717 Odocoileus virginianus right humerus. Scale bars equal 20 mm. Image Credit: Palaeontologia Electronica
Push back the known date of Appalachian deer
East Tennessee State University’s Gray Fossil Site is a site already well-known for ancient tapirs, rhinos, and bears. Before this discovery, deer fossils were not known from Appalachian Pliocene sites. Now we know deer roamed these ancient forests long before the advent of modern species.
“Overall similarity of the Eocoileus specimens to modern deer (Odocoileus spp.) suggest the former occupied comparable niches, being versatile browsers well-suited to occupy a broad range of habitats. [This discovery] suggest[s] deer have filled a similar role in the forests of the Appalachian region for nearly 5 million years, persisting through dramatic changes in climate and biota over time.” the researchers wrote in their paper.
Not a new species, but gives new information
The researchers conducted detailed measurements comparing the finds with a broad range of fossil and modern deer. These Tennessee fossils matched up strikingly well with Eocoileus gentryorum specimens previously found in Florida. The comparison gave researchers enough confidence to state that the fossils belong to the same species.
Tibiae of Eocoileus gentryorum from the Gray Fossil Site, TN in anterior view, along with a comparative sample of fossil and extant cervids: A) ETMNH 8030 Eocoileus gentryorum right tibia; B) ETMNH 14923 Eocoileus gentryorum right tibia; C) UF 212246 Eocoileus gentryorum proximal left tibia; D) UF 68022 Eocoileus gentryorum distal left tibia; E) UF 276268 Odocoileus virginianus left tibia; F) AMNH 35301 Capreolus capreolus left tibia. Scale bars equal 20 mm. Image Credit: Palaeontologia Electronica
The nearly identical morphology of the Tennessee and Florida specimens suggests deer spread swiftly across North America during the late Miocene–Early Pliocene.
“Dated to 4.9-4.5 Ma, the [Gray Fossil Site] deer are among the earliest records of the family in North America and combined with similar age occurrences from Florida and Washington these indicate deer dispersed rapidly across the continent in the latest Miocene or Early Pliocene. “