Today, the Perissodactyls include only three families and 18 species: eight species of equines, five of tapiridae and five of rhinocerotidae. But these mammals, characterized by an odd number of fingers on the hind limbs, were much more numerous during the Eocene, a period extending from 56 to 33.9 million years ago and marked by the appearance then the massive disappearance of animal and plant species. A recent study thus presents two new species belonging to this order.
Two new Iberian species
Before the “Great Cut” 33.9 million years ago, the Perissodactyls included 16 families, 13 more than today. Among those extinct were the Palaeotheridae (Paleotheriidae), also called pseudo-horses. This nickname comes from the fact that researchers believe they looked a lot like modern equines, even though Palaeotherids are no more related to horses than to rhinos or tapirs.
A group of researchers from the University of the Basque Country, led by Leire Perales Gogenola, took an interest in this family, and more particularly in specimens of the genus Leptolophus, found on Iberian soil. The analysis of the teeth of 16 specimens led to the discovery of two new species of these distant cousins of the horse, endemic to the Iberian Peninsula: Leptolophus cuestai and Leptolophus franzeni.
To understand the uniqueness of these specimens, we must remember the paleogeographic context in which these species flourished. While at the beginning of the Eocene there is a global warming, the waters rise and submerge the coasts of Europe. The Old Continent is therefore in the form of an archipelago.