They were split based mainly on the work by Stiles (1996), but the taxa east (americana group and murallae) and west (corvina group) of the Andes had actually been considered separate species until they were merged into a single species by Meyer de Schauensee in 1952.
variable valve timing | Yellow-bellied Seedeater | Variable (programming) | White-collared Seedeater | Variable valve timing | Variable surface glycoprotein | variable star | variable (programming) | Variable-message sign | variable-message sign | Variable-length code | Variable-incidence wing | Variable Hawk | Variable Geometry | Variable geometry | Variable elimination | Variable data printing | Variable cost | Variable capacitor | Variable bitrate | Variable Assembly Language | variable | RR Lyrae variable | New Zealand's bush is variable in appearance, but generally the term connotates densely forested areas, like this one around Lake Gunn | metasyntactic variable | Local hidden variable theory | Limited dependent variable | Green's function for the three-variable Laplace equation | ''dependent'' or ''response'' variable | Copper Seedeater |