Oregon paleontologists identify 30-million-year-old proto-dog fossil

Paleontologists in the northwestern United States have identified a 30-million-year-old fossil of a proto-dog, Mesocyon coryphaeus. The specimen, which includes leg bones, hips, ribs, vertebrae, and a baculum, was discovered in a rock slab in eastern Oregon.

Previously thought to be an oreodont, a type of extinct mammal, recent re-examination confirmed the specimen is a primitive canid roughly the size of a coyote. Paleontologist Anne Kort from the University of Michigan noted that a hereditary bone growth on the carpus helped confirm the species. These ancient canids likely hunted small equids and other hoofed mammals. This discovery provides significant insight into canid evolution, following the Hesperocyon, which lived approximately 40 million years ago.