RESUMO
Specimens of Imparfinis schubarti (Gomes, 1956) collected in the Piumhi river drainage, state of Minas Gerais, Brazil, were studied cytogenetically. The river was diverted from the Rio Grande Basin into the São Francisco basin in the early 1960s. All individuals presented 2n = 58 chromosomes, including 18 metacentric, 34 submetacentric and six subtelocentric chromosomes. A secondary constriction was observed in the interstitial region of the long arm of the largest chromosome pair, coinciding with the NOR. A single conspicuous heterochromatic block located in the largest pair of metacentric chromosomes was observed, adjacent to the secondary constriction. A detectable 18S rDNA probe hybridization region occurs in only one chromosome pair and is synthenic with the marking obtained with 5S rDNA probe. These results fit the cytogenetic pattern previously described for the genus Imparfinis Eigenmann & Norris, 1900.
RESUMO
Specimens of Imparfinis schubarti (Gomes, 1956) collected in the Piumhi river drainage, state of Minas Gerais, Brazil, were studied cytogenetically. The river was diverted from the Rio Grande Basin into the São Francisco basin in the early 1960s. All individuals presented 2n = 58 chromosomes, including 18 metacentric, 34 submetacentric and six subtelocentric chromosomes. A secondary constriction was observed in the interstitial region of the long arm of the largest chromosome pair, coinciding with the NOR. A single conspicuous heterochromatic block located in the largest pair of metacentric chromosomes was observed, adjacent to the secondary constriction. A detectable 18S rDNA probe hybridization region occurs in only one chromosome pair and is synthenic with the marking obtained with 5S rDNA probe. These results fit the cytogenetic pattern previously described for the genus Imparfinis Eigenmann & Norris, 1900.
RESUMO
Specimens of Imparfinis schubarti (Gomes, 1956) collected in the Piumhi river drainage, state of Minas Gerais, Brazil, were studied cytogenetically. The river was diverted from the Rio Grande Basin into the São Francisco basin in the early 1960s. All individuals presented 2n = 58 chromosomes, including 18 metacentric, 34 submetacentric and six subtelocentric chromosomes. A secondary constriction was observed in the interstitial region of the long arm of the largest chromosome pair, coinciding with the NOR. A single conspicuous heterochromatic block located in the largest pair of metacentric chromosomes was observed, adjacent to the secondary constriction. A detectable 18S rDNA probe hybridization region occurs in only one chromosome pair and is synthenic with the marking obtained with 5S rDNA probe. These results fit the cytogenetic pattern previously described for the genus Imparfinis Eigenmann & Norris, 1900.
RESUMO
Tetragonopoterus aeneus Hensel (1870) is removed from synonymy with Astyanax fasciatus (Cuvier, 1819), revalidated and redescribed as A. henseli to avoid homonymy. Astyanax henseli differs from A. fasciatus stricto sensu and other Astyanax species by the presence of two to four maxillary teeth, two vertically-elongated humeral spots, dentary tooth cusps positioned close to one another, and the slender form of the dentary teeth.
Tetragonopterus aeneus Hensel (1870) é retirada da sinonimia de Astyanax fasciatus (Cuvier, 1819), revalidada e redescrita como A. henseli para evitar homonímia. Astyanax henseli diferencia-se de A. fasciatus stricto sensu e das demais espécies de Astyanax pela presença de dois a quatro dentes no maxilar, duas manchas humerais verticalmente alongadas, cúspides dos dentes do dentário situadas próximas entre si, e dentes do dentário relativamente estreitos.
RESUMO
Tetragonopoterus aeneus Hensel (1870) is removed from synonymy with Astyanax fasciatus (Cuvier, 1819), revalidated and redescribed as A. henseli to avoid homonymy. Astyanax henseli differs from A. fasciatus stricto sensu and other Astyanax species by the presence of two to four maxillary teeth, two vertically-elongated humeral spots, dentary tooth cusps positioned close to one another, and the slender form of the dentary teeth.
Tetragonopterus aeneus Hensel (1870) é retirada da sinonimia de Astyanax fasciatus (Cuvier, 1819), revalidada e redescrita como A. henseli para evitar homonímia. Astyanax henseli diferencia-se de A. fasciatus stricto sensu e das demais espécies de Astyanax pela presença de dois a quatro dentes no maxilar, duas manchas humerais verticalmente alongadas, cúspides dos dentes do dentário situadas próximas entre si, e dentes do dentário relativamente estreitos.