Genetic data and niche differences suggest that disjunct populations of Diglossa brunneiventris are not sister lineages

Disjunct distributions within a species are of great interest in systematics and biogeography. This separation can function as a barrier to gene flow when the distance among populations exceeds the dispersal capacity of individuals, and depending on the duration of the barrier, it may eventually lead to speciation. Here we describe patterns of geographic differentiation of two disjunct populations of Diglossa brunneiventris separated by approximately 1000 km along the Andes. Diglossa brunneiventris vuilleumieri is isolated in northern Colombia, while Diglossa brunneiventris brunneiventris has a seemingly continuous distribution across Peru, Bolivia, and Chile. We sequenced mitochondrial and nuclear DNA of the two Diglossa brunneiventris subspecies to evaluate whether they form a monophyletic clade, while including the other three species within the carbonaria complex (D. gloriosa, D. humeralis and D. carbonaria). We also constructed ecological niche models for each Diglossa brunneiventr...