Paleontologists at John Hopkins University School of Medicine are celebrating the discovery of what some are calling a ‘missing link’ that shows horses, rhinos, and tapirs all had a common ancestor. They dubbed the newly found creature Cambaytherium thewissi.
The horses, rhinos, and tapirs we know today belong to the biological order Perissodactyla, which means ‘odd-toes ungulates,’ or animals that have an uneven number of toes on their hind feet and share a distinctive digestive system.
Although paleontologists knew of Perissodactyla fossils dating from as far back as 56 million years ago, evidence of their earlier evolution was lacking, said lead researcher Dr. Ken Rose from Johns Hopkins University School of Medicine, in a report by The Daily Mail. Now, however, Rose and his colleagues have discovered an intermediate form linking Perissodactyla to a more ancient animal.
Back in 2001, Rose’s team and their Indian colleagues started exploring certain Eocene sediments in what is now western India for evidence of Perissodactyla. Working at the edge of an open-pit coal mine in Gujarat, they unearthed a treasure trove of ancient bones and teeth dating back to about 54.5 million years ago.
The wealth of fossils also is providing insight into the period when the Indian subcontinent was still an island inching toward a collision with Asia—raising the possibility that Cambaytherium originated there.
Interestingly, however, even when India was separated from the mainland, it had primates similar to those that roamed Europe at the time, Rose said in a report by ZeeNews. A possible explanation is that at some point in India’s seafaring sojourn, it passed close enough to the Horn of Africa or the Arabian peninsula that a land bridge formed, allowing two-way migration for their inhabitants.
Nevertheless, Cambaytherium’s unique features suggest that the Indian land mass remained isolated from both Africa and Asia for quite some time.
The researchers provide details of their discovery online in the journal Nature Communications.