JOHNSON CITY, Tenn. (AP) — East Tennessee State University says researchers have discovered evidence of the extinct “bone-crushing” dog at a fossil site that also included herbivores, a sabretooth cat and alligators.

The university says it identified the Borophagus dog at the Gray Fossil Site by finding a single right humerus upper arm bone. The “bone-crushing” animal had powerful teeth and jaws.

A single right humerus (upper arm bone) of a Borophagus, or “bone-crushing” dog was identified at the site, and research on it was carried out by Emily Bōgner, a doctoral student at the University of California, Berkeley, and Dr. Joshua Samuels, associate professor in the ETSU Department of Geosciences and curator at the Gray Fossil Site and Museum.

David Moscato, the Science Communication Specialist at the Gray Fossil Site, says that the fossil is unique in more ways than one. “What’s so cool about our Borophagus, or our bone-crushing dog, is that it is a new type of large predator that we haven’t found before at the Gray Fossil Site. And it’s the first time we’ve identified any members of the dog family at Gray.”

Moscato stated that the Borophagus would have the same bone-crushing strength as a  hyena.

There are also reasons why this find is so unique, “Most of the time Borophagus dogs like this are found in ancient grasslands and open habitats. The Gray Fossil Site is an ancient forest. So even though these kinds of dogs have been found in other fossil sites, ours is already an oddball for living in an ecosystem that we normally don’t find these dogs.”

The university says this is the first evidence of a dog there. The animal has been discovered at dozens of fossil sites across the U.S and Mexico, usually alongside plants and animals from open environments like grasslands.

Fossils at the Gray Fossil Site depict a densely forested habitat with lots of forest plants and tree-dwelling animals.

To read more about this unique discovery and other prehistoric finds – check out this link to the Gray Fossil Museum.