Genetic evidence for a species complex within the piranhaSerrasalmus maculatus (Characiformes Serrasalmidae) fromthree Neotropical river basins based on mitochondrial DNAsequences

摘要

Mitochondrial molecular markers (DNA sequences of D-loop, cytochrome b andcytochrome c oxidase I) were employed to characterize populations of the piranha from Upper Paraná, Upper Paraguay andTocantins River basins. D-loop sequences of population from Paraná-Paraguay River basin exhibited tandem repeats of shortmotifs (12 base pairs) and variable numbers depending on specimens, accountingfor length variation. Concatenated mitochondrial sequences suggested that encompasses different mitochondrial DNAlineages. Although sampling was restricted to three river basins, phylogeneticanalysis clearly indicated that the species currently recognized as presents high genetic variability. Maximum likelihood andBayesian analysis clustered populations accordingto their locations. However, the highest genetic differentiation was identifiedbetween populations from Paraná-Paraguay system and Tocantins River basin. Threespecies delimitation analyses (PTP, GMYC, and ABGD) suggested that there are atleast two species among the analyzed populations. The analysis of themitochondrial sequences evidenced genetic differentiation among populationscorresponding to related, but different species, suggesting that at least from the Tocantins River and Paraná-ParaguayRiver basins are most likely different species. Therefore, should be considered a species complex withmorphologically cryptic diversity. An integrative revision is suggested.