Abstract
In the present work, cytogenetic studies were performed in Corumbataia cuestae, a member of the subfamily Hypoptopomatinae (Siluriformes, Loricariidae). The specimens were collected in the Lapa Stream, a tributary of the Passa-Cinco River (Sao Paulo State, Brazil). It presented 2n=54 chromosomes with a karyotype constitution of 14M+10SM+3ST/A. Only 2 nucleolar organizing regions were observed in the terminal region of the short arm of the metacentric pair 2. Both were heteromorphic in size, while sequential analyses of the metaphases in Giemsa/silver and Giemsa/C-banding showed that the secondary constrictions correspond to NORs. The constitutive heterochromatin pattern was clearly observed in the nucleolar chromosome pair with large pericentromeric heterochromatic blocks. In the present study the authors report the hypothesis of conservation in the status of the karyotypic macrostructure of the species as compared to other species studied in the subfamily Hypoptopomatinae. Therefore, this study brings a contribution to base the phylogenetic correlations between the Corumbataia genus and other genera in the group.
