July 18, 2008
The ancestors of modern-day primates in the Americas had tiny brains just like their counterparts in Africa and Eurasia, according to a new study.
Because modern anthropoid, or humanlike, primates in both regions have large brains relative to their body sizes, the finding suggests that one of the hallmarks of primate biology—increasing brain size—happened independently in isolated groups.
Both sides today have large brains, so that transformation has to have occurred subsequent to the evolutionary split," between New World primates and Old World monkeys, said John Finarelli, a study co-author and evolutionary biologist at the University of Michigan in Ann Arbor.