Cleveland -- Fossils of a new hoofed mammal that resembles a cross between a dog and a hare which once roamed the Andes Mountains in southern Bolivia around 13 million years ago was discovered by Darin A. Croft, assistant professor of anatomy at the Case Western Reserve University School of Medicine and a research associate at the Cleveland Museum of Natural History.
With Federico Anaya from Universidad Autnoma Toms Fras, Croft reported on the new mammal find named Hemihegetotherium trilobus in the Journal of Vertebrate Paleontology article, "A New Middle Miocene Hegetotherid (Notoungulata: Typotheria) and a Phylogeny of the Hegetotheriidae." It is named for the distinctive three lobes on its back lower molar teeth.
The animal belonged to a group of animals called notoungulates--hoofed mammals native only to South America. The group originated in South America soon after the dinosaurs went extinct and evolved to include hundreds of species over a span of more than 50 million years; all of them are now extinct. Although most notoungulates were gone before humans got to South America, some of the earliest humans to journey to that continent may have seen the last living notoungulates.
For most of the time the notoungulates were living in South America, the continent was an island, isolated from both Antarctica and North America. The main groups of mammals living there were marsupials (like opossums), rodents, monkeys, armadillos, sloths, and various hoofed mammals.
The notoungulates were the most diverse group of hoofed animals in South America before it was reconnected to North America through the Panama land bridge about two to three million years ago. This reconnection began an exchange of mammals between the two continents and dramatically changed the types of mammals found in South America today.
The fossil specimens were collected from the Quebrada Honda and Rio Rosario areas of Bolivia, near the bord
Contact: Susan Griffith
Case Western Reserve University