A new study now points out how a group of mammals including horse, rhinos and tapirs evolved thanks to a trail of fossil family.
The research, published in the Journal of Paleontology, provides an answer to the debated question on where did hoofed animals evolved. The study concluded that they evolved in or near present day India.
The 15-year-long study pieces together an almost complete picture of the skeletal anatomy of the Cambaytherium. The Cambaytherium was an extinct cousin of the perissodactyls that live on the Indian subcontinent some 55 million years ago.
The research was selected for publication as part of the famed Society of Vertebrate Paleontology Memoir Series.
First described in 2005, the Cambaytherium is the most primitive member of an extinct group that branched off just before the evolution of perissodactyls, providing scientists with unique clues to the origins and evolution of hoofed mammals.
The findings of the Cambaytherium included a sheep-sized animal with moderate running ability and features that were in-between perissodactyls and mammal forerunners.
When comparing its bones with living and extinct mammals, researchers found that they represented an evolutionary stage more primitive that the known perissodactyls and supported the concept that they originated in or near India before dispersing to other continents.
Ken Rose, the lead author of the study stated that the modern even-toed ungulates, Perissodactyls, and Primates appeared abruptly at the beginning of the Eocene around 56 million years ago. However, their geographic source has always remained a mystery.
Rose added that in 1990, Krause & Maas proposed that these orders might have evolved in India during its northward drift from Madagascar and armed with the concept, Rose and his team decided to journey to India to find the source.
While the first trip to Rajasthan in 2001 bore little success, in 2004, the team was able to return to the Vastan Mine in Gujarat where one of their Belgian collaborators, Thierry Smith found the first mammal fossils, including Cambaytherium.
According to researchers, the Cambaytherium likely evolved in isolation in or near India during the Paleocene.