Systematics of early and middle Miocene Old World monkeys S.M. Hassan, M.K. Abdel Gawad, M.A. Hamdan, A.N. El-Barkooky, Brenda R. Benefit, Monte L. McCrossin, M. G. Leakey, Ellen R. Miller, E.L. Simons, J.M. Plavcan • 2009