Chromosome analysis in Saccodon wagneri (Characiformes) and insights into the karyotype evolution of Parodontidae

ABSTRACT Parodontidae is a relatively small group of Neotropical characiform fishes consisting three genera (Apareiodon, Parodon, and Saccodon) with 32 valid species. A vast cytogenetic literature available on Apareiodon but to date, there no data about Saccodon, genus that contains only species trans-Andean distribution. In the present study karyotype S. wagneri was described, based both conventional (Giemsa staining, Ag-NOR, C-bands) molecular (repetitive DNA mapping by fluorescent in situ hybridization) methods. diploid chromosome number 2n = 54 observed sexes, presence heteromorphic sex chromosomes ZZ/ZW type detected. The W has terminal heterochromatin band occupies approximately half long arm, being this size Z chromosome. FISH assay showed synteny 18S-rDNA 5S-rDNA genes pair 14, absence interstitial telomeric sites. Our reinforce hypothesis conservative structure suggest an ancient origin family.