Phylogeography of Hypostomus strigaticeps (Siluriformes: Loricariidae) inferred by mitochondrial DNA reveals its distribution in the upper Paraná River basin

In this study, phylogenetic and phylogeographic analyses of populations identified as Hypostomus strigaticeps from the upper Parana River basin were conducted in order to test whether these different populations comprises cryptic species or structured populations and to assess their genetic variability. The sequences of the mitochondrial DNA ATP sintetase (subunits 6/8) of 27 specimens from 10 populations (one from Mogi-Guacu River, five from Paranapanema River, three from Tiete River and one from Peixe River) were analyzed. The phylogeographic analysis showed the existence of eight haplotypes (A-H), and despite the ancestral haplotype includes only individuals from the Tiete River basin, the distribution of H. strigaticeps was not restricted to this basin. Haplotypes A, B and F were the most frequent. Haplotypes D, E, F, G, and H were present in the sub-basin of Paranapanema, two (A and B) were present in the sub-basin of the Tiete River, one (C) was exclusively distributed in the sub-basin of the Peixe River, and one (B) was also present in the sub-basin of the Grande River. The phylogenetic analysis showed that the populations of H. strigaticeps indeed form a monophyletic unit comprising two lineages: TG, with representatives from the Tiete, Mogi-Guacu and Peixe Rivers; and PP, with specimens from the Paranapanema River. The observed degree of genetic divergence within the TG and PP lineages was 0.1% and 0.2%, respectively, whereas the genetic divergence between the two lineages themselves was approximately 1%. The results of the phylogenetic analysis do not support the hypothesis of existence of crypt species and the phylogeographic analysis confirm the presence of H. strigaticeps in other sub-basins of the upper Parana River: Grande, Peixe, and Paranapanema sub-basins. Neste estudo, foram conduzidas analises filogeneticas e filogeograficas de populacoes identificadas como Hypostomus strigaticeps na bacia do alto rio Parana a fim de testar se essas populacoes compreendem especies cripticas ou populacoes estruturadas e avaliar a variabilidade genetica das mesmas. Foram analisadas sequencias do DNA mitocondrial ATP sintetase (subunidades 6/8) de 27 especimes de 10 populacoes (uma do rio Mogi-Guacu, cinco do rio Paranapanema, tres do rio Tiete e uma do rio do Peixe). A analise filogeografica mostrou a existencia de oito haplotipos (A-H), e apesar do haplotipo ancestral incluir apenas individuos da bacia do rio Tiete, a distribuicao de H. strigaticeps nao se restringe a esta bacia. Os haplotipos A, B e F foram os mais frequentes. D, E, F, G e H estao presentes na sub-bacia do rio Paranapanema, dois (A e B) estao presentes na sub-bacia do rio Tiete, um (C) esta exclusivamente distribuido na sub-bacia do rio do Peixe, e um (B) tambem esta presente na sub-bacia do rio Grande. A analise filogenetica mostrou que as populacoes de H. strigaticeps realmente formam uma unidade monofiletica que compreende duas linhagens: TG, com representantes do rio Tiete, rio Mogi-Guacu e rio do Peixe, e PP, com especimes do rio Paranapanema. O grau de divergencia genetica observada nas linhagens de TG e PP foram de 0,1% e 0,2%, respectivamente, enquanto que a divergencia genetica entre as duas linhagens foi de aproximadamente 1%. Os resultados da analise filogenetica nao suportam a hipotese da existencia de especies cripticas e a analise filogeografica confirma a presenca de H. strigaticeps em outras sub-bacias do alto rio Parana: sub-bacias do rio Grande, rio do Peixe e rio Paranapanema.