Edited by Eric Delson, American Museum of Natural History, New York, NY and accepted by the Editorial Board January 28, 2013 (received for review August 7, 2012)
The modern Old World Monkeys (Superfamily Cercopithecoidea, Family Cercopithecidae) can be traced back into the late Miocene, but their origin and subsequent diversification is obscured by the scarcity of terrestrial fossil sites in Africa between 15 and 6 Ma. Here, we document the presence of cercopithecids at 12.5 Ma in the Tugen Hills of Kenya. These fossils add 3 My to the known antiquity of crown Cercopithecidae. The two specimens represent one or possibly two species of early colobine, and their morphology suggests that they were less folivorous than their modern relatives.
Author contributions: J.B.R. and A.H. designed research; J.B.R. and A.H. performed research; J.B.R., C.C.G., and A.H. analyzed data; and J.B.R., C.C.G., and A.H. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. E.D. is a guest editor invited by the Editorial Board.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1213691110/-/DCSupplemental.
