Abstract
Several hypotheses have been proposed to explain the origin of euprimates (primates of modern aspect, including living primates). In his Perspective, Sargis highlights the report by Bloch and Boyer, who have discovered a fossil that allows these hypotheses to be tested. The 56-million-year-old skeleton of Carpolestes simpsoni, an early primate, has an opposable big toe with a nail rather than a claw, but lacks euprimate visual specializations (such as forward-facing eyes and orbits) and was not adapted for leaping. It seems, therefore, that grasping evolved in primates before visual specializations and leaping.