Phylogeography and population genetic structure of the cardinal tetra (Paracheirodon axelrodi) in the Orinoco basin and Negro River (Amazon basin): evaluating connectivity and historical patterns of diversification

The Neotropics contain one of the most diverse assemblages of freshwater fishes worldwide. Part of this diversity is shared between the Orinoco and Amazon basins. These basins have been separated for a long time due to the Vaupes Arch, rising between 10 - 11 Ma. Today, there is only one permanent connection between the Orinoco and Negro (Amazon) basins, known as the Casiquiare Canal. However, alternative corridors allowing fish dispersion between both basins have been proposed. The cardinal tetra (Paracheirodon axelrodi), the most important fish in the ornamental world market, is distributed in both basins. Here we investigated P. axelrodi phylogeography, population structure, and potential routes of migration and connectivity between the two basins. A total of 468 bp of the mitochondrial gene (COI), 555 bp of the nuclear gene fragment (MYH6), and 8 microsatellite loci were analyzed. As a result, we found two major genetic clusters as the most likely scenario (K=2), but they were not di..., Muscle tissue samples (one per individual) were collected along the Orinoco and Amazon basins on the distribution area for P. axelrodi. Once the fish were received, they were euthanized by rapid chilling (hypothermic shock) on ice. Then, all individuals and tissue samples were preserved in ethanol at 95% and stored at 4°C. Genomic DNA was extracted., The data files included are Excel files(.xlsx)