New species of “horned” turtle identified from Gray Fossil Site

The Gray Fossil Site in Gray, Tennessee preserves a five-million-year-old ecosystem once home to rhinos, mastodons, red pandas, and many more extinct species which made their home in and around an ancient pond. Among the most common fossil animals found at the site are turtles.

A recent study has identified an extinct species of painted turtle which is entirely new to science and unique to the Gray Fossil Site. It has been named Chrysemys corniculata, or the “horned painted turtle.” The name comes from a conspicuous pair of pointy projections on the front edge of the shell.

A fossil shell of the new species, Chrysemys corniculata. The species is named the “horned painted turtle” because of the two small pointed projections on the front edge of the shell. Image from Steven Jasinski.

This research was published in the Zoological Journal of the Linnean Society by Dr. Steven Jasinski, professor at the Harrisburg University of Science and Technology and alumnus of ETSU’s paleontology Master’s program.

These turtles are represented at Gray by numerous well-preserved shells, allowing for a thorough description of this unique species. The “horns” on the shell are similar to those found on the males of modern-day painted turtles.

“A big difference in Chrysemys corniculata is that the ‘horns’ are present in both sexes, although they appear to be larger in males,” says Jasinski. “It is likely they were sexual display features.”

An artistic reconstruction of the extinct species Chrysemys corniculata. Art by Sergey Krasovskiy.

These turtles would have been right at home in the ancient pond of the Gray Fossil Site, which also hosted slider turtles, snapping turtles, and other semi-aquatic species. Fossil evidence shows that painted turtles have been around for 35 million years, and modern painted turtles are extremely common across the United States, including in Tennessee. This new discovery at Gray helps scientists to unravel the ancient history of this familiar group of reptiles. 

Chrysemys corniculata may have preferred slightly warmer temperatures,” says Jasinski. “As conditions changed, C. picta (modern painted turtles) were potentially able to overtake the other species, making them the most widespread turtles in modern North America.”

Dr. Steven Jasinski examines a modern painted turtle in East Tennessee. Image from Steven Jasinski.

This is the third new species of fossil turtle to be identified from the Gray Fossil Site. The first two were the musk turtle Sternotherus palaeodorus and the slider turtle Trachemys haugrudi.

“The Gray Fossil Site is truly the gift that keeps on giving," says Dr. Blaine Schubert, Executive Director of the Center of Excellence in Paleontology at East Tennessee State University and a professor in the Department of Geosciences. "Our extensive collection of turtles continues to provide exciting new discoveries that fill important gaps in the fossil record of North America.”

Fossils of this new species are now on display at the Gray Fossil Site & Museum.

Steven E Jasinski, A new species of Chrysemys (Emydidae: Deirochelyinae) from the latest Miocene-Early Pliocene of Tennessee, USA and its implications for the evolution of painted turtles, Zoological Journal of the Linnean Society, 2022;, zlac084,