Timing the origin of New World monkeys.

The origin of New World monkeys (Infraorder Platyrrhini) has been an extensively debated issue. In this study, we analyzed mitochondrial genomes from Cebus (Platyrrhini), Homo, Hylobates, Pan, Pongo (Hominoids), Macaca, Papio (Cercopithecoids), and Tarsius (outgroup) to investigate this matter. Two distinct methodologies were employed on mitochondrial genes to estimate divergence times: the traditional likelihood ratio test performed in ML analyses of individual and concatenated gene sequences and the recent multigene Bayesian approach. Using the Cercopithecoid-Hominoid split as calibration point (25 MYA), our results show consistently that Platyrrhines split from Catarrhines at around 35 MYA. Although the main focus of the study is New World monkey origins, we have also estimated other primate divergence times: Homo-Pan at 5-7 MYA; Pongo-(Homo/Pan) at 13-16 MYA; Hylobates-(Pongo/Homo/Pan) at 15-19 MYA; and Macaca-Papio at 10-12 MYA. Our estimate for the origin of New World monkeys is in agreement with the hypothesis of a transatlantic journey from Africa to South America, as suggested by the fossil record.