Ancient bones from South America proved to be those of a previously unknown animal, a small hippidion horse with distinct DNA. Scientists also discovered a new species of ass that lived on the plains of Eurasia as recently as 50,000 years ago. The study was published in the Proceedings of the National Academy of Sciences.
Orlando et al. Revising the recent evolutionary history of equids using ancient DNA. Proceedings of the National Academy of Sciences, 2009
