Hoofed animals like horses and rhinos evolved from a strange sheep-sized animal that looked like a cross between a pig and a dog and roamed in India almost 55 million years ago., researchers have claimed.
Experts from Johns Hopkins University who explored mines in Gujarat discovered the remains of the strange creature called Cambaytherium.
Cambaytherium is an extinct cousin of perissodactyls (the group of mammals that includes horses, rhinos, and tapirs) that lived on the Indian subcontinent almost 55 million years ago.
The first trip to Rajasthan in 2001 had little success, “Although we found only a few fish bones on that trip, the following year our Indian colleague, Rajendra Rana, continued exploring lignite mines to the south and came upon Vastan Mine in Gujarat,” said Ken Rose, emeritus professor at Johns Hopkins University and lead author of the study.
This new mine proved much more promising.
“In 2004, our team was able to return to the mine, where our Belgian collaborator Thierry Smith found the first mammal fossils, including Cambaytherium,” Rose said in a paper published in the Journal of Vertebrate Paleontology.
Encouraged, the team returned to the mines in Gujarat and collected fossilised bones of Cambaytherium and many other vertebrates, despite challenging conditions.
Cambaytherium represents an evolutionary stage more primitive than any known perissodactyl, supporting origin for the group in or near India –before they dispersed to other continents when the land connection with Asia formed.
Researchers said the animal likely evolved at a time India was still an island.
The results also confirm a theory first proposed 30 years ago that the origin of horses can be traced to India during its northward drift from Madagascar.
“In 1990, Krause & Maas proposed that these orders might have evolved in India, during its northward drift from Madagascar, dispersing across the northern continents when India collided with Asia,” Rose said.
The latest finding is the culmination of 15 years of work by a global team of researchers and involved piecing together the complete skeletal anatomy of Cambaytherium from over 350 fossils unearthed throughout India.
Despite the abundance of perissodactyls in the Northern Hemisphere, Cambaytherium suggests that the group likely 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.
Cambaytherium, first described in 2005, is the most primitive member of an extinct group that branched off just before the evolution of perissodactyls.