Can molecular data place each neotropical monkey in its own branch?

Four different DNA datasets, representative of all extant neotropical primate genera, were tandemly aligned, comprising some 6,763 base pairs (bp) with 2,086 variable characters and 674 informative sites. Maximum Parsimony, Maximum Likelihood and Neighbor-Joining analyses suggested three monophyletic families (Atelidae, Pitheciidae and Cebidae) that emerged almost at the same time during primate radiation. Combined molecular data showed congruent branching inside the atelid clade, placing Alouatta as the most basal lineage followed by Ateles and a more derived branch including Brachyteles and Lagothrix as sister groups. In the Pitheciidae, Callicebus was the most basal lineage with respect to Pithecia and to the more derived sister groups (Cacajao and Chiropotes). Conjoint analysis strongly supported the monophyly of the Cebidae, grouping Aotus, Cebus and Saimiri with the small callitrichines. Within callitrichines, Cebuella merged with Callithrix, Callimico appeared as a sister group of Callithrix/Cebuella, Leontopitecus as a sister group of the previous clade, and Saguinus was the earliest callitrichine offshoot. Two major points remained to be clarified in platyrrhine phylogeny: (i) the exact branching pattern of Aotus, Cebus, Saimiri and the callitrichines, and (ii), which two of these three families (Atelidae, Pitheciidae and Cebidae) are more closely related to one another.