title: Spatial and temporal patterns of diversification on the Amazon: A test of the riverine hypothesis for all diurnal primates of Rio Negro and Rio Branco in Brazil.
abstract: The role of Amazonian rivers as drivers of speciation through vicariance remains controversial. Here we explore the riverine hypothesis by comparing spatial and temporal concordances in pattern of diversification for all diurnal primates of Rio Negro and its largest tributary, Rio Branco. We built a comprehensive comparative phylogenetic timetree to identify sister lineages of primates based on mitochondrial cytochrome b DNA sequences from 94 samples, including 19 of the 20 species of diurnal primates from our study region and 17 related taxa from elsewhere. Of the ten primate genera found in this region, three had populations on opposite banks of Rio Negro that formed reciprocally monophyletic clades, with roughly similar divergence times (Cebus: 1.85 Ma, HPD 95% 1.19-2.62; Callicebus: 0.83 Ma HPD 95% 0.36-1.32, Cacajao: 1.09 Ma, 95% HPD 0.58-1.77). This also coincided with time of divergence of several allopatric species of Amazonian birds separated by this river as reported by other authors. Our data offer support for the riverine hypothesis and for a Plio-Pleistocene time of origin for Amazonian drainage system. We showed that Rio Branco was an important geographical barrier, limiting the distribution of six primate genera: Cacajao, Callicebus, Cebus to the west and Pithecia, Saguinus, Sapajus to the east. The role of this river as a vicariant agent however, was less clear. For example, Chiropotes sagulata on the left bank of the Rio Branco formed a clade with C. chiropotes from the Amazonas Department of Venezuela, north of Rio Branco headwaters, with C. israelita on the right bank of the Rio Branco as the sister taxon to C. chiropotes+C. sagulata. Although we showed that the formation of the Rio Negro was important in driving diversification in some of our studied taxa, future studies including more extensive sampling of markers across the genome would help determine what processes contributed to the evolutionary history of the remaining primate genera.
authors.affiliation: School of Environment and Life Sciences, 315 Peel Building, University of Salford, Salford M5 4WT, UK; Instituto Nacional de Pesquisas da Amazonia INPA, Manaus, Brazil. Electronic address: j.p.boubli@salford.ac.uk.
authors.forename: Jean P
authors.initials: JP
authors.lastname: Boubli
authors.affiliation: Instituto Nacional de Pesquisas da Amazonia INPA, Manaus, Brazil. Electronic address: camilaribas@gmail.com.
authors.forename: Camila
authors.initials: C
authors.lastname: Ribas
authors.affiliation: Institute for Society and Genetics, 1321 Rolfe Hall, University of California, Los Angeles, CA 90095, USA; Department of Anthropology, University of California, Los Angeles, CA 90095, USA. Electronic address: jlynchalfaro@ucla.edu.
authors.forename: Jessica W
authors.initials: JW
authors.lastname: Lynch Alfaro
authors.affiliation: Institute for Society and Genetics, 1321 Rolfe Hall, University of California, Los Angeles, CA 90095, USA; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA. Electronic address: michaelalfaro@ucla.edu.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Alfaro
authors.affiliation: Instituto Nacional de Pesquisas da Amazonia INPA, Manaus, Brazil. Electronic address: mndasilva@gmail.com.
authors.forename: Maria Nazareth F
authors.initials: MN
authors.lastname: da Silva
authors.affiliation: Universidade Federal do Amazonas, Laboratório de Evolução e Genética Animal, Manaus, AM, Brazil. Electronic address: gabriela.m.pinho@gmail.com.
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Pinho
authors.affiliation: Universidade Federal do Amazonas, Laboratório de Evolução e Genética Animal, Manaus, AM, Brazil. Electronic address: izeni@evoamazon.net.
authors.forename: Izeni P
authors.initials: IP
authors.lastname: Farias
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D001938:Brazil; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D049810:Genetic Speciation; D014644:Genetic Variation; D005843:Geography; D008957:Models, Genetic; D010802:Phylogeny; D051078:Platyrrhini / Q000145:classification* / Q000235:genetics; D045483:Rivers; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial; D045303:Cytochromes b
keywords: Amazonia; Phylogeography; Platyrrhini; River barrier; Riverine hypothesis; Vicariance