Diagnostic molecular markers for the females of Phlebotomus (Paraphlebotomus) caucasicus and P. mongolensis were sought by characterizing from individual Iranian specimens a gene fragment, namely mitochondrial cytochrome b, that had previously proven useful for the taxonomy of phlebotomine sandflies. Males of both species were used as reference material because their external genitalia provide the only diagnostic morphological characters. A phylogenetic analysis of the new sequences, and those previously reported for P. grimmi, found no support for recognizing more than one species (P. caucasicus s.l.) in Iran. Most of the genetic variation was geographical. An absence of lineage sorting was demonstrated, and it is proposed that any search for species-specific molecular markers for these three taxonomic species should be continued by applied biologists only if there is better evidence for associating any one of them with phenotypes important for understanding the transmission of Leishmania species in foci of zoonotic cutaneous leishmaniasis.
