Estudo taxonômico das espécies do gênero Hypostomus Lacépède, 1803 (Siluriformes, Loricariidae) de rios do leste do Brasil

Abstract

The most diverse fish fauna of the world is found in freshwater systems of the Neotropical region. Loricariidae is the richest endemic family of the order Siluriformes in South America and the genus Hypostomus belonging to this family is one of the most notable in function of richness and ambiguous taxonomy. Although studies concerning to genus Hypostomus have been presented, some gaps still remain in the taxonomic studies of this genus mainly in the Eastern Brazilian Basins. Thus, this study has as objective to realize a taxonomic study of the species of the genus Hypostomus Lacépède, 1803, from the basins of rivers, Doce, Jequitinhonha, Mucuri and Paraíba do Sul, which are part of the eastern Brazilian basins. We studied specimens of Hypostomus from those basins, in comparison with material from the adjacent rivers Tietê, São Francisco, São Mateus and other small coastal basins. The studied morphological characters include 12 meristic characters and 24 body measurements. Measurements were analyzed in form of body proportions, and measurements of widely distributed species were evaluated through analysis of canonical discriminant. At the studied basins, four species of the genus Hypostomus were found. Hypostomus affinis (Steindachner, 1876) and Hypostomus auroguttatus Kner, 1854 were identified in the Doce, Mucuri and Paraíba do Sul rivers, showing morphological and morphometric variations among the populations from these basins. Hypostomus nigrolineatus Zawadzki; Carvalho; Birindelli & Azevedo, 2016 and Hypostomus sp. were identified from the Jequitinhonha river basin. The morphological and morphometric variations observed along the distribution of the different species are discussed in relation to the isolation and geography of the drainage. Considering the difficulty of species identification, hard taxonomic problems and scarce data from the original descriptions, comments on the taxonomy of the species in the studied basins are presented.