Molecular evolution of the Asian francolins (Francolinus, Galliformes): A modern reappraisal of a classic study in speciation

Abstract

We investigated the evolution of the Asian francolins, five little known species in the genus Francolinus (Phasianidae). Evolutionary affinities of two of these species, F. gularis (swamp francolin) and F. pondicerianus (grey francolin), has long remained unclear. In contrast, the other three species, F. pintadeanus (Chinese francolin), F. pictus (painted francolin) and F. francolinus (black francolin) have been cast among the “spotted francolins” on a morphological and ecological basis. Previous molecular DNA investigations including Asian francolins mostly relied upon partial gene sequencing of one specimen per species (no more than three species and with the exclusion of F. pictus). Therefore, fundamental questions do persist. What relationship exists among the spotted and the other Asian francolins? What is the geographic origin of the black francolin, the species with the largest distribution range? How did the geological history influence the diversification of francolins across Asia? We sequenced the entire Control Region of the mitochondrial DNA in 228 samples of all five Asian francolin species, which were collected in 16 countries (from East Europe to East Asia). We constructed a molecular phylogeny according to four different procedures. We showed the monophyly of each of the Asian francolins and the spotted group, while that of the entire Asian group was presumed according to a biogeographical model we proposed. The splitting of the genus Francolinus occurred ∼17.4Ma (95% HPD: 13.4–22.1) while the spotted francolins diverged ∼10.5Ma (7.0–14.9). We resolved the most recent common ancestor to painted and black francolin as being in the Indian sub-continent, thus suggesting a westwards adaptive radiation of the latter. In Pakistan, we identified F. f. asiae representatives in the Northern Areas and in the Sindh. The latter represents a relict population of Indian fauna within the Pakistani range of the Great Rann of Kachchh.