Diversidade genética e taxonômica de Myleini (Teleostei: Characiformes) nas bacias do Alto Rio Paraguai, Alto Rio Tapajós e Madeira, Brasil

Abstract

Serrasalmidae harbor species popularly known as piranhas and pacus, currently with 100 valid species, distributed throughout the hydrographic basins of the Neotropical region. They are mainly characterized by having a tall body, small scales and a serrated keel along the belly. Among the genera belonging to this family, Piaractus, popularly known as pacu, pacu caranha, pacu guaçu and Utiaritichthys known as pacu rubber stand out. It is a family that presents taxonomic problems and has been the target of several studies based on analyzes of different DNA sequences, aiming to solve both the taxonomic and phylogenetic uncertainties already detected in previous studies. In this context, molecular genetics has enabled the development of tools to genetically characterize individuals and populations and the study of genetic diversity and variability, within and between populations. These studies are necessary for an adequate management of fish species as a way to seek alternatives to mitigate the problems related to the preservation of genetic diversity and fish stocks in natural environments. Therefore, the objective of this study was to use molecular and morphological tools for the study of Piaractus mesopotamicus and Utiaritichthys sennaebragai, with the aim of evaluating the identity, diversity and genetic variability of these species in the Paraguay and Amazon basins, more specifically in the headwaters of some tributaries of the Alto Tapajós and Madeira basins. For this, the work is composed of two chapters: "Chapter 1" that addresses the genetic variability of Piaractus mesopotamicus (Holmberg, 1887) using ddRadSeq to study population genetics and "Chapter 2" that addresses the integrative taxonomy of Utiaritichthys sennaebragai (Characiformes; Serrasalmidae) in the Amazon and Upper Paraguay basins. For Chapter 1, SNPs (Single Nucleotide Polymorphism) were used, in order to understand how this population, so widely distributed throughout the upper Paraguay River basin, behaves genetically, and for Chapter 2, DNA barcode and morphometry were used in order to analyze specimens initially identified as belonging to Utiaritichthys sennaebragai, originating from the upper Paraguay, upper Tapajós and Madeira river basins (Amazon basin), using an integrative approach, in order to answer whether the species currently registered only for the Amazon basin can also occur in the Upper Paraguay basin and whether the Molecular Operational Taxonomic Units (MOTUs) identified correspond to one or more species that are distributed across the different hydrographic systems studied.