A ZZ/ZW sex chromosome system in a new species of the genus Parodon (Pisces, Parodontidae)

Abstract

A chromosome analysis was carried out in two sympatric fish species of the genus Parodon, Parodon sp. and P. tortuosus, from the Paraná basin, São Paulo State, Brazil. Although both species showed the same diploid number (2n=54), an interspecific diversity was detected concerning their karyotypic formulas and banding patterns, besides a ZZ/ZW sex chromosome system detected in Parodon sp., which was caracterized as a new species for this genus. No heteromorphic sex chromosomes were found in P. tortuosus. These data are discussed concerning the characterization of the regional ictiofauna and its evolutionary aspects. © 2002 Taylor & Francis Group, LLC.