Did you know horses, rhinoceros evolved in India over 50 million years ago

Horses, rhinoceros, tapirs, and many other such mammals evolved in India more than 50 million years ago, an international team of fossil hunters has found, analysing hundreds of tiny pieces of fossils retrieved from a lignite mine in Gujarat over 15 years.

With more than 350 new fossils, the study pieces together a nearly complete picture of the skeletal anatomy of the Cambaytherium – a sheep-sized extinct cousin of the ancestors of horses and rhinos that lived on the Indian subcontinent almost 55 million years ago.

The research sheds new light on a lingering mammal mystery - how odd-toed hoofed ungulates like horses, zebras, tapirs, and rhinos (perissodactyls), even-toed hoofed ungulates like cattle, deer, antelope, and sheep (artiodactyls), and primates suddenly appear in the fossil record at the beginning of the Eocene period (about 56 million years ago) across the northern continents during a very short period of global warming.

These animals were not known before this abrupt appearance and scientists don't know how and where they evolved.

Paleontologists led by Kenneth Rose at Johns Hopkins University decided to explore India nearly two decades ago following a 1990 hypothesis that such animals might have evolved in the country during its northward drift from Madagascar, dispersing across the northern continents when India collided with Asia.

They landed in India to test the proposition but the first trip to Rajasthan in 2001 brought little success. Next year one of the team members Rajendra Rana from HNB Garhwal University went deep inside Vastan lignite mine in Gujarat and found its maiden success.

In 2004 the team that also includes Kishor Kumar from Wadia Institute of Himalayan Geology, Dehradun and Thierry Smith from Royal Belgian Institute of Natural Sciences discovered the first mammal fossil including that of Cambaytherium.

Over the years they accumulated teeth, jaws, and skeletal elements that revealed its unique anatomy.

“We didn't know what we would find or if we would find anything at all since there were no fossils of this age known from India before our work. Cambaytherium was a particular surprise because of its remarkable combination of primitive and advanced anatomical features,” Rose, an emeritus professor at Johns Hopkins University and lead author of the study told DH.

The team pieced together missing blocks to know more about Cambaytherium, an animal with moderate running ability.

It combines some features showing a clear relationship with perissodactyls, together with many primitive features found in earlier “archaic” hoofed mammals but not in perissodactyls.

The existence of Cambaytherium suggests that such animals were likely to have evolved in isolation in or near India during the Paleocene (66-56 million years ago), before dispersing to other continents when the land connection with Asia formed.

“The research is important to understand the origin and evolution of early mammals. It's a more detailed account of their 2014 research paper in which the team first proposed that ungulates like horses originated in India,” commented GVR Prasad, a paleontologist at Delhi University, who is not associated with the research.

This study would be published in the Society of Vertebrate Paleontology Memoir Series, a special yearly publication.