Although Astyanax bimaculatus is the most representative species of the genus in the Amazon region, there are no cytogenetic studies of A. bimaculatus species in Amazon region. Thus, we aimed to analyse the chromosome complements of specimens from this area using classic and molecular cytogenetic approaches. The results revealed the existence of a distinct cytotype and this is the first report of the occurrence of a B microchromosome in the species. Overall, these data indicate that the karyotypic evolution of this species is complex, involving the occurrence of chromosomal rearrangements.
Keywords: Amazon coastal zone; Astyanax bimaculatus; biodiversity; chromosomal rearrangements; heterochromatin; karyotypic diversity.
© 2022 Fisheries Society of the British Isles.