Out of the shadows: Multilocus systematics and biogeography of night monkeys suggest a Central Amazonian origin and a very recent widespread southeastward expansion in South America.

Night monkeys (Aotus, Cebidae) are a widely distributed genus of Neotropical primates with a poorly understood taxonomy and biogeography. The number of species in the genus varies from one to nine, depending on the author, and there are at least 18 known karyotypes, varying from 2n = 46 to 2n = 58. Historically, night monkeys are divided into two species groups: red- and grey-necked groups from south and north of the Amazon-Solimões River, respectively. Here, we used 10 nuclear and 10 mitochondrial molecular markers from a wide taxonomic and geographic sample to infer phylogeny, divergence times, and biogeography of the genus. For phylogenetic reconstruction we used Maximum Likelihood (ML) and Bayesian Inferences (BI). Biogeographic models were generated using the 'BioGeoBEARS' software. We found support for nine taxa of Aotus and rejected the existence of monophyletic "red necked" and "grey necked" species groups. We suggest a taxonomic reclassification of the genus, which is better represented by two clades named northern group, which contains Aotus miconax, A. nancymae, A. trivirgatus, A. vociferans, A. lemurinus, A. griseimembra, A. zonalis, and A. brumbacki, and southern group, which contains A. nigriceps, A. boliviensis, A. infulatus, and A. azarae. The results suggest that the most recent common ancestor of all species of Aotus arose in the central Amazon basin in the Early Pliocene. The evolutionary history of night monkeys was guided by dispersal, vicariance and founder events. The end of the Andean uplift and the subsequent changes in the Amazon landscape, as well as the Amazon-Solimões and Tapajós rivers may have played an important role in the origin and diversification of Aotus, respectively. However, most of the Amazonian rivers seem not to have been geographical barriers to dispersal of night monkeys. The herein named southern group is fruit of a very recent diversification guided by dispersal, crossing the Tapajós, Xingú, Tocantins, and Guapore rivers and reaching the Cerrado in the last 1.6 My.

Phenotypic evolution in marmoset and tamarin monkeys (Cebidae, Callitrichinae) and a revised genus-level classification.

Marmosets and tamarins (Cebidae, Callitrichinae) constitute the most species-rich subfamily of New World monkeys and one of the most diverse phenotypically. Despite the profusion of molecular phylogenies of the group, the evolution of phenotypic characters under the rapidly-emerging consensual phylogeny of the subfamily has been little studied, resulting in taxonomic proposals that have limited support from other datasets. We examined the evolution of 18 phenotypic traits (5 continuous and 13 discrete), including pelage, skull, dentition, postcrania, life-history and vocalization variables in a robust molecular phylogeny of marmoset and tamarin monkeys, quantifying their phylogenetic signal and correlations among some of the traits. At the family level, our resulting topology supports owl monkeys (Aotinae) as sister group of Callitrichinae. The topology of the callitrichine tree was congruent with previous studies except for the position of the midas group of Saguinus tamarins, which placement as sister of the bicolor group did not receive significant statistical support in both Maximum Parsimony and Bayesian Inference analyses. Our results showed that the highest value of phylogenetic signal among continuous traits was displayed by the long call character and the lowest was exhibited in the home range, intermediate values were found in characters related to osteology and skull size. Among discrete traits, pelage and osteology had similar phylogenetic signal. Based on genetic, osteological, pelage and vocalization data, we present an updated genus-level taxonomy of Callitrichinae, which recognizes six genera in the subfamily: Callimico, Callithrix, Cebuella, Mico, Leontopithecus and Saguinus. To reflect their phenotypic distinctiveness and to avoid the use of the informal "species group", we subdivided Saguinus in the subgenera Leontocebus, Saguinus and Tamarinus (revalidated here).