Hydrographic basins dictate the genetic structure of the paradoxical frog Pseudis bolbodactyla (Anura: Hylidae) in the rivers of Central Brazil.

The article investigates how hydrographic basins influence the genetic structure of the semiaquatic paradoxical frog *Pseudis bolbodactyla* in Central Brazil’s rivers, testing the Riverine Thruway Hypothesis (RTH) and the ‘one basin–one species’ hypothesis. Genetic analyses of 166 samples across the Paraná (PR), Araguaia–Tocantins (AT), and São Francisco (SF) basins revealed three distinct lineages corresponding to these basins, with limited gene flow primarily occurring within basins and some historical migration from PR to the ancestor of AT and SF. Divergence times coincide with Late Miocene to Pleistocene orogenic events shaping the Brazilian Shield, suggesting that *P. bolbodactyla* likely represents a species complex structured by hydrographic boundaries. These findings highlight the dual role of rivers as facilitators of gene flow within basins and barriers among them, with implications for understanding diversification and taxonomy in Neotropical semiaquatic fauna.