Learning About the Role of Rivers in the Distribution of Genetic Diversity of a Neotropical Primate

ABSTRACT Aim We aimed to evaluate the genetic diversity and demographic history of an arboreal and forest‐dependent species, the black‐fronted titi monkey ( Callicebus nigrifrons ), and tested if the distribution of its genetic variability is influenced by the Grande River, which is the major river inside the area of the distribution of the species. Location The sampling localities were spread throughout the entire distribution area of C. nigrifrons in southeastern Brazil. Taxon Black‐fronted titi monkey, Callicebus nigrifrons (Primates: Pitheciidae). Methods We assessed the population genetic structure and performed molecular variance, phylogenetic and demographic history analyses using single nucleotide polymorphisms (SNPs) derived from Genotyping by Sequencing (GBS) and mitochondrial markers (COI and Cyt b ). Results The spatial distribution of the genetic clusters based on neutral SNPs and mitochondrial haplogroups evidenced the partitioning of populations by the major river within the geographic distribution of C. nigrifrons . SNPs revealed signs of an ancient demographic decrease in both populations from each side of the main channel of the Grande River. On the other hand, the mitochondrial analyses pointed to a slight population expansion dating during the Holocene for both populations, suggesting an increase of suitable areas for the species in this period. Main Conclusions We supported the hypothesis of the influence of rivers on the distribution of genetic diversity of C. nigrifrons . Such inferences shed light on the potential effects of historical barriers and climate changes on the distribution pattern of the genetic variability of the titi monkeys, considering their current geographic occurrence.