Early Eocene Cantius torresi—oldest primate of modern aspect from North America

Abstract

The oldest primates of modern aspect (primates of prosimian tarsiiform-lemuriform or higher grade) are known from Lower Eocene strata of Sparnacian age in Europe^1,2, Bumbanian age in Asia^3,4, and Wasatchian age in North America⁵. These first appearances coincide on all three northern continents with initial records of Artiodactyla, Perissodactyla and other modern mammalian groups appearing approximately 53 Myr BP^6,7. Here I report that a newly discovered basal Wasatchian f aunal assemblage older than any known previously includes the well-preserved dental remains of a new species of Cantius, the earliest representative of Eocene Adapidae and the oldest evidence of primates of modern aspect known from North America. This new Cantius is possibly ancestral to all later adapids, including the European Donrussellia and North American Pelycodus. Cantius torresi has premolars reminiscent of those in Omomyidae, suggesting that earlier lemuriform and tarsiiform primates were closely related and little differentiated at the beginning of the Eocene.