Phylogeographic Pattern and Extensive Mitochondrial DNA Divergence Disclose a Species Complex within the Chagas Disease Vector Triatoma dimidiata

Abstract

We propose that Groups I-IV, as well as T. hegneri, should be regarded as separate species. In the Petén of Guatemala, representatives of Groups I, II, and III occur in sympatry; the absence of haplotypes with intermediate genetic distances, as shown by multimodal mismatch distribution plots, clearly indicates that reproductive barriers actively promote within-group cohesion. Some sylvatic specimens from Belize belong to a different species - likely the basal lineage of the T. dimidiata complex, originated ~8.25 Mya. The evidence presented here strongly supports the proposition that T. dimidiata is a complex of five cryptic species (Groups I-IV plus T. hegneri) that play different roles as vectors of Chagas disease in the region.