Estudo da diversidade e das relações filogenéticas do gênero Astyanax (Characiformes. Characidae) baseado em sequências de DNA

• Ano de defesa: 2015
• Autor(a) principal: Rossini, Bruno César [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Peixe - Distribuição geografica; Peixe - Identificação; Astyanax (Peixe); Filogenia; Análise de DNA; Astyanax; Fishes
• Link de acesso: http://hdl.handle.net/11449/140217; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/16-06-2016/000866307.pdf

The Characidae family is the most species rich between the order Characiformes. One such species rich genera, with many taxonomic conflicts is Astyanax, which comprises currently 142 species, of which 52 were described in the last ten years. In this study we present an extensive geographic sampling of the genus Astyanax with specimens from South and Central America, covering almost the entire distribution of the genus. In this context, the genus was examined by two approaches, one about the diversity of species and another focusing on the phylogenetic relationships of the group. The diversity study was based on barcode sequences, of which the 5' portion of Cytochrome Oxidase subunit I gene, proposed as standard tool to separate species at the molecular level, thus helping the taxonomic studies and the discovery of new species. The use of different approaches to clustering sequences (ABGD, GMYC and BIN analysis) show a consistency of results obtained with the initial cutoff value of 2%, but GMYC tends to identify a larger number of groups than other analyzes. The results point to the existence of four major groups in the genus, comprising 122 species groups, but in many cases, several species are grouped into a single cluster, making identification by DNA barcode virtually impossible. For the phylogeny analysis of the genus based on multilocus molecular, data shows that Astyanax is polyphyletic and at least four lineages, which are formed by the species complexes A. scabripinnis and A. fasciatus, other by complex A. bimaculatus, a lineage with specimens from Central America and other with species from coastal regions of South America. In addition, some species of Astyanax are related with genera such as Moenkhausia and Jupiaba, known to be morpholgical similar. All Astyanax are present in Clade C, with only exception of A. festae, who was in Clade A, and then we propose its review. Final data from this study point to a very complex ...