Oligocene Tortoise Stylemys
Stylemys nebrascensis
Brule Formation
Middle Oligocene
Niobrara County, Wyoming
Here is a near perfect Stylemys that has a real story to tell. Besides being a really fine example of the species, the shell was used as a den for an Oligocene rodent! The shell has several rodent-gnawed portals that clearly show the tooth marks. This outstanding example shows excellent detail and has no distortion. Both carapace and plastron are complete and there is only a tiny bit of restoration on the margin. The shell detail is good and would be a top-rate addition to any serious White River collection. This specimen is better that any seen in most museums.

Stylemys (meaning pillar turtle) is the first fossil genus of dry land tortoise belonging to the order Testudines discovered in the United States. The genus lived in temperate to subtropical areas of North America, Europe, and Asia, based on fossil distribution. The genus was first described in 1851 by Dr. Joseph Leidy. The tortoise was common in the prehistoric Badlands, especially Nebraska and South Dakota. Stylemys is found throughout the White River Group from Chadronian through Whitneyan age. It also occurs in Oregon, California, Utah, Texas, Wyoming, and Colorado. Few Badlands fossils are more abundant, widely distributed, or better preserved than this genera. The shell body is often preserved with remarkable perfection, but upon exposure by erosion, they disintegrate quickly. Associated bones and skulls are rarely found. Fossil tortoise eggs of this genus have also been found in the host formation.