Data from: The role of rivers as geographical barriers in shaping genetic differentiation and diversity of Neotropical primates

We quantitatively tested the riverine barrier hypothesis and its influence
on biogeographical distributions and molecular variation in New World
monkeys (Parvorder: Platyrrhini). Using mitochondrial markers (cytochrome
oxidase subunit II and cytochrome b), we analyzed taxonomic differences
and the effects of geographical barriers on molecular patterns across
Central and South America. Nearly 80% of described species are separated
by geographical barriers, including several mountain chains. River width
exhibited a negative correlation with molecular similarity in adjacent
taxa for both molecular markers. Several presently described taxa were not
supported based solely on these molecular phylogenetic markers, including
Saimiri, Mico, Cebus, Sapajus, and Cherecebus. These taxonomic issues are
far more common where river barriers do not exist. In conclusion, we found
a significant correlation between river width and molecular divergence in
adjacent taxa, indicating that wider rivers were associated with greater
molecular divergence for two commonly used mitochondrial genes. Species
boundaries were predominantly found at river interfaces, and in the
absence of discernable geological barriers, adjoining species were more
likely to exhibit molecular similarity. Our findings suggest that river
and mountain barriers are significantly associated with gene flow for
neotropical primate taxa. Additionally, river width proves to be a
valuable tool for estimating molecular divergence in adjacent taxa,
particularly in regions with limited sampling.