Chromosomal population structuring in carangids (Perciformes) between the north-eastern and south-eastern coasts of Brazil.

The family Carangidae comprises 151 species, of which only 19 have been so far karyotyped, including a few representatives from the Western Atlantic Ocean. This study compared the cytogenetic features of three Atlantic carangids, Chloroscombrus chrysurus, Trachinotus goodei and T. falcatus, from north-eastern Brazilian coast, with previously obtained cytogenetic data from southern populations. All species presented 2n = 48 chromosomes. Chloroscombrus chrysurus showed a conserved karyotypic macrostructure (2n = 48a, FN = 48) whereas T. goodei (2m + 2sm + 44a; FN = 52) and T. falcatus (2n = 10m/sm + 38a; FN = 58) presented more diversified karyotypes. Data showed that the samples of C. chrysurus from the north-eastern and south-eastern regions did not differ cytogenetically. However, the frequency or position of ribosomal sites (Ag-NOR/18S rDNA) were effective in discriminating the populations of Trachinotus between these coastal regions. The distinct chromosomal patterns suggest a historical genetic fractionating of the Trachinotus populations along the Brazilian coast. [ABSTRACT FROM AUTHOR]