Fig. 1: Map of South America indicating the H. malabaricus localities analyzed.

The colors indicate the different hydrographic basins in Brazil listed in the legend and the colored circles indicate the collection sites, with the corresponding karyomorphs found as: A blue, B pink, C yellow, D red, F green, and G black. The ellipse indicates a site with sympatry for both karyomorphs A and D. The ideograms on the right represent partial karyotypes of each karyomorph and their sex chromosomes. Pairs of karyomorphs with homologous sex chromosomes are boxed (see the text). Karyomorphs C and D differ from A and B by micro-rearrangements, though the details are not yet fully clear.