Whole genomes of the amazonian Cacajao reveal complex connectivity and fast differentiation driven by high environmental dynamism

Despite showing the greatest primate diversity on the planet, genomic studies on Amazonian primates show very little representation in the literature. With 48 geolocalized high coverage whole genomes from wild uakari monkeys, we present the first population-level study on platyrrhines using whole genome data. In a very restricted range of the Amazon rainforest, eight uakari species ( Cacajao genus) have been described and categorized into bald and black uakaris, based on phenotypic and ecological differences. Despite a slight habitat overlap, we show that posterior to their split 0.92 Mya, bald and black uakaris have remained independent, without gene flow. Nowadays, these two groups present distinct genetic diversity and group-specific variation linked to pathogens. We propose differing hydrology patterns and effectiveness of geographic barriers have modulated the intra-group connectivity and structure of uakari populations. Beyond increasing their representation, with this work we explored the effects of the Amazon rainforest’s dynamism on platyrrhine species. ### Competing Interest Statement The authors have declared no competing interest.