New York, Oct 9 (IANS): The discovery of new bones from a large land mammal that lived in the Indian subcontinent about 48 million years ago has led scientists to identify a new branch of mammals closely related to modern horses, rhinos and tapirs.

This family of anthracobunidae was commonly considered to be the ancestors of modern elephants and sea cows.

Geographically, this was a puzzling idea because elephants and their relatives were groups that were known from Africa not Asia.

These fossils indicate that anthracobunids are related to the tiny tapirs that are commonly found in Pakistan and that perissodactyls probably originated in Asia.

Anthracobunids are just one of many lineages of vertebrates that evolved from being terrestrial animals to live in a shallow water habitat and had thick bones.

"These thick bones probably acted like ballast to counteract body buoyancy. You can see that kind of bone structure in modern hippos, otters, penguins and cormorants," said Lisa Noelle Cooper from the Northeast Ohio Medical University in the US.

The study appeared in the journal PLOS ONE.