Molecular identification and phylogenetic analysis of Siluriformes from the Paraguay River basin, Brazil.

The objective of this study was to identify, through the DNA barcode, fishable Siluriformes which were collected from the Paraguay River basin in Pantanal. It was analyzed for genetic distance calculation using the Kimura-two-model parameters and the dendrogram was builtusing the Neighbour-Joining algorithm. The average genetic distance within species, genus and families were 0.2%, 1.6% and 4.2%, respectively. These values were lower than those reported in studies from other continents, probably due to the recent radiation process undergone by Neotropical fish. The dendrogram revealed two possible cases of hybridization, one individual Pseudoplatystoma corruscans, it was not possible to identify whether it was a natural event or commercial production exhaust and other of Pimelodus cf. argenteus leading to the assumption that the aspects of reproductive isolation cannot be clearly defined. Besides, the populations of the species Hemisorubim platyrhynchos and e Platydora armatulus may be undergoing a substructuring process, with genetic differences 3% and 4%, respectively.