We examined chromosomes of three species of the genus Hypostomus, in order to contribute to the understanding of the karyotype evolution of this group. Specimens of H. ancistroides and H. nigromaculatus displayed differences in karyotype formulas, distribution and location of heterochromatin and nucleolus organizer regions when compared to other populations of the same species. We made the...

Cytogenetic analyses using C-banding and chromosomal digestion by several restriction enzymes were carried out in four populations (named A, B, C and D) of Hypostomus prope unae (Loricariidae, Hypostominae) from Contas river basin, northeastern Brazil. These populations share 2n=76 and single NORs on the second metacentric pair but exclusive karyotype forms for each locality. Populations A and ...

Resource partitioning is essential for coexistence of phylogenetically related species in altered environments, where changes biotopes can limit resources and change ecological strategies. We investigated resource between two congeneric catfishes (Hypostomus affinis H. luetkeni) three niche dimensions (trophic, spatial, temporal) a Neotropical reservoir. tested the hypothesis that use different...

Abstract: A new species of Phanerothecium Kritsky & Thatcher, 1977 (Oogyrodactylidae Harris, 1983) is described from locariid fish southeast Brazil. macrosomum n. sp. (Oogyrodactylidae) the body surface Hypostomus regani (Ihering, 1905) (Loricariidae). It characterized by an armed male copulatory organ containing spines different size proximal to distal extremity, short peduncle and robust ...

In this study, which is the first karyotype analysis of Hypostomus iheringii, nine specimens collected in Córrego da Lapa (tributary of the Passa-Cinco River) showed a diploid number of 80 chromosomes. Silver nitrate staining and fluorescence in situ hybridization (FISH) with an 18S rDNA probe revealed the presence of multiple nucleolus organizer regions (NORs) (chromosome pairs 13, 20, and 34)...

Several cytogenetic markers show chromosomal diversity in the fish such as "armoured catfish". Although studies have characterized many species in the major genera representing these Siluridae, particularly in the genus Hypostomus Lacépède, 1803, trends in chromosome evolution of this group remain unclear. The Paraíba do Sul river basin contains the armoured catfish Hypostomus affinis Steindach...