Cytogenetic studies in species of family Loricariidae (Osteichthyes, Siluriformes) from Iguatemi river basin, Brazil. First cytogenetic report inFarlowella amazonum(Günther, 1864)

Abstract

In this work, we analyzed the karyotypes of three species of the Loricariidae family. Hypostomus ancistroides, from the Dourado and Água Boa Streams, had 2n = 68 chromosomes, with nucleolar organizer regions (NORs) in multiple chromosomal pairs and few chromosomes marked in centromeric and telomeric regions after C-banding. Hypostomus strigaticeps, from the Água Boa Stream, had 2n = 72 chromosomes with NORs in multiple chromosomal pairs. The chromosomal data of Farlowella amazonum, described here for the first time, consist of 58 chromosomes, with NORs in one chromosomal pair. The pattern of NORs seems to be quite typical among the subfamilies of Loricariidae, i.e. multiple NOR for Hypostominae (Hypostomus ancistroides and Hypostomus strigaticeps) and simple NOR for Loricariinae (Farlowella amazonum).