Table 1.

Chromosomal formula, sex chromosome system occurrence, W-specific probe sites and 18S rDNA sites on the chromosomes of the Characidium species/populations analysed.

Species	River	Chromosomal Formula	Sex System	W probe sites	18S rDNA sites/localization	Figure 3 relation
C. zebra	Passa Cinco	♂ ♀ 32 m+18 sm	Absent	Dispersed in autosomes	23 pair/subterminal	(a)
C. lauroi	Grande stream	♂ 32 m+18 sm ♀ 31 m+18 sm+1st	ZZ/ZW	Autosomal and dispersed in the W chromosome	Z and W/terminal	(b)
C. gomesi	Alambari	♂ ♀ 32 m+18 sm	ZZ/ZW	Z in proximal region of the long arm, entire m W chromosome and some terminal minor sites over autosomes	Z and W/terminal and 19 pair/terminal in just one homologue in males	(c and d)
C. gomesi	Grande	♂ ♀ 32 m+18 sm	ZZ/ZW	Z in proximal region of the long arm, entire m W chromosome and some terminal minor sites over autosomes	17 pair/terminal	(e and f)
C. gomesi	Minhoca stream	♂ ♀ 32 m+18 sm	ZZ/ZW	Z in proximal region of the long arm, entire m W chromosome and some terminal minor sites over autosomes	17 pair/terminal	(g)
C. gomesi	Verde	♂ 32 m+18 sm ♀31 m+18 sm+1st	ZZ/ZW	Z in proximal region of the long arm, entire st W chromosome and some terminal minor sites over autosomes	17 and 22 pairs/terminal and just one homologue of pairs 1 and 20/terminal	(h)