Analysis of the mitochondrial D-Loop reveals that neither river boundaries nor geographic distance structure the fine-scale genetic variation of an Amazonian treefrog

While most anurans have limited vagility and local fidelity, there are some exceptions. In the present study, we used Boana boans, a large treefrog found throughout most of the Amazon basin, as a model organism. We investigated the possible isolation of the B. boans demes located on opposite margins of the Juruena River and their population structure. We sampled 14 individuals of B. boans and analyzed the mitochondrial D-Loop to verify whether the river or Euclidean distance is acting as barrier to the dispersal of this frog. The sequencing revealed 12 haplotypes, with global Fst values of - 0.079, K2P values ranging from - 0.187 to 0.054, and primarily intrapopulation (81.78%) genetic diversity, with only 18.22% of the variation being found among populations. Analysis of molecular variance and Bayesian cluster analysis detected a lack of genetic structuring within the study area. The model species presented a capacity for dispersal over long distances in comparison with most other amphibians, which, together with its resistance to desiccation and reproductive mode, enable this treefrog to disperse across rivers and overland. In the specific case of Juruena River, many fluvial islands present within the study area may also be favorable to the dispersal of the species.