Stylemys nebrascensis, Tortoise/Turtle

The tortoises of the Badlands are one of the most abundant, and are certainly among the most fascinating vertebrates from the Brule Formation. Joseph Leidy, in 1852, described Stylemys nebrascensis from several specimens collected by John Evans of the U.S. Geological Corp in an expedition to the Territory in 1849. Stylemys nebrascensis was the first fossil turtle described from North America. Specimens of these tortoises range in size from as small as 5cm to as large as a meter long. All of the land turtles found in the Oligocene deposits of the central Western Interior are described as either Stylemys, Gopherus, or Hesperotestudos. The extant genus Gopherus has long been thought to have been derived from the Oligocene genus Stylemys, but recently paleontologists have concluded that perhaps the extant genus Gopherus existed in the Oligocene as well. Distinctions between Gopherus and Stylemys are very minor. There are three modern descendants of these tortoises living in North America