New Findings Suggest Odd-Toed Ungulates Originated On Continental "Noah's Ark"

Illustration of the compelling Cambaytherium thewissi by Elaine Kasmer.

As reported on the Science Daily website, John Hopkins University researchers excavating fossils at the edge of a coal mine in India have recently made a discovery which brings revelations on the origins of odd-toed ungulates. Although past research has traced the presence of these animals back to the early Eocene epoch fifty-six million years ago, details on their earlier evolution is shrouded in mystery. The odd-toed ungulates, classified in the order Perissodactyla, include modern day horses and rhinos and are distinguished from other orders due to their uneven number of toes and unique digestive system. Following the proposition of perissodactyls having their origins in Western India, the John Hopkins University research team took to Eocene sediments in this region and unearthed several remains of the little-known ungulate Cambaytherium thewissi. According to these researchers, the teeth, number of sacral vertebrae, and hand and feet bones of Cambaytherium suggest that it is the species most like a common ancestor to all members of Perissodactyla yet discovered. Apart from filling an evolutionary gap, this finding also supports the notion that a diverse number of early mammal groups might have evolved in India while it was still an isolated island continent. This isolation would allow the groups, which included lemur-like primates and both perissodactyls and the even-toed artiodactyls, to evolve without competition from other Paleocene animals.
 As detailed in Dr. Donald Prothero and Dr. Robert Shoch's Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals (a book I recently purchased which has rekindled my strong interest in the ungulates), several scientists have previously suggested that India acted as a sort of "Noah's Ark" which allowed the dispersal of these groups to the rest of the globe following its collision with Asia at the start of the Eocene. The sudden presence of some mammal genera such as the chevrotain-like artiodactyl ancestor Diacodexis in European and North American Eocene sediments without evolutionary precedent certainly suggests that such a hypothesis is more than plausible. The recent Cambaytherium discoveries have apparently yielded "the first concrete evidence" to support this hypothesis, and thus hold even more interesting implications as to the evolution of significant early mammal groups. It is my hope that future research from the aforementioned John Hopkins University researchers who are continuing their work at nearby mines will reveal more exciting data on the evolutionary history of ungulates and other significant early mammal groups.

Tim Morris' illustration of the ancestral artiodactyl Diacodexis, quite  fittingly referred to as a "bunny deer" by some.