Siluriformes corresponds to the group with the highest number of species among clades belonging to the Ostariophysi, with 3,093 species, of which 117 belong to Hypostomus. With 80 species found in Brazilian rivers, this is the dominant genus of catfishes in Brazil. According to available data in the literature, the diploid number in this group varies from 2n = 54 in Hypostomus plecostomus a 2n = 84 in Hypostomus sp. 2. This genus shows a wide morphological diversity in the pattern of staining, difficulting identification of their species, especially those shows wide geographical distribution.Due to the taxonomic complexity, some chromosomal markers may help in the characterization, identification and comparison of different species in this genus. Thus, this study aims to characterize, using classical cytogenetics techniques (conventional Giemsa staining, C banding and by silver nitrate impregnation - Ag-NOR) and molecular (fluorescent in situ hybridization with probes for 18S and 5S rDNA) some species of Hypostomus from the basins of São Francisco and Upper Paraná rivers, helping to understand of matters of cytotaxonomy, as well as a better understanding of karyotype evolution of some species of this genus.
News published in Agência FAPESP Newsletter about the scholarship: