Filogeografia de traíras Hoplias malabaricus (Bloch, 1794) (Teleostei, Erythrinidae) das bacias hidrográficas da América do Sul

• Autor(a) principal: Santos, Udson
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1381
• topic: Filogeografia; Peixes; América do Sul; Paleohidrografia; Phylogeography; Fish; South America; Paleohidrografia; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA ANIMAL

South America is the continent with the largest number of freshwater fish species. To understand which facts were responsible for this diversification, analyses considering paleoclimatic, geomorphologic and paleohidrologic effects in the cladogenesis of widely distributed taxa are necessary. Phylogeographic patterns of Hoplias malabaricus populations from South America basins were characterized in this study with DNA sequences (mitochondrial and nuclear) and cytogenetic data, including results in paleohidrologic scenario and comparing not related fish fauna distribution. Two hundred and eighty-three specimens were analyzed. Bayesian and maximum parsimony analyses were performed with mitochondrial ATP synthase 6 gene (ATPase6). Haplotypes networks with ATPase6 and recombination activating nuclear 2 (RAG2) genes were constructed with Network 4.6.1.1. Software. Time divergence between haplogroups was estimated using ATPase6 gene sequences on BEAST 1.5.1. Software. North/northwest of South America was identified as H. malabaricus origin center and on Miocene this taxon expanded its distribution to the southern part of the continent. The diploid number reduction from 42 to 40 chromosomes was already established at this time. During Pliocene, canyon and Sete Quedas waterfalls were forming and populations with 2n = 40C from the lower Paraná River were separated from those from the upper part of the basin, where 2n = 39/40D karyomorph was established. The ATPase6 gene variation in Amazon Basin, indicated two possible scenarios: during the lower Pliocene, there was a second diploid number reduction in H. malabaricus, or there was gene flowing between specimens with 2n=40 and 2n=42 chromosomes. After lower Pliocene, 2n = 40F karyomorph settled in São Francisco, Parnaíba and northeast Brazilian coastal river basins. During Pleistocene, paleo-channels with freshwater on Brazilian Coast allowed gene flowing among H. malabaricus populations, today isolated in this region. The evolution and diversification of H. malabaricus populations, and probably other freshwater fish species from South America, are due to three main factors. The first is the implications of the Andes upflit, which brought important paleohidrologic changes and consequently changes on South America H. malabaricus distribution. The second factor involves local dynamics of stream piracy due to geological faults reactivation or differential erosion processes, which lead some drainages to present a mosaic of genealogical lineages that differed in neighboring basins (eg. upper Paraná). The third factor involves the glacial dynamics, leading to confluence and subsequent separation of river basins on coastal geomorphological sections and consequently a small genetic distance among populations today isolated.