Taxonomic revision of the red-fronted Tinkerbird Pogoniulus pusillus (Dumont, 1816) based on molecular and phenotypic analyses

Abstract

Red-fronted Tinkerbird Pogoniulus pusillus (Dumont, 1816) presently comprises three recognised subspecies, of which two are found in East Africa and one occurs disjunctly in southern Africa. Based on their respective distributions and phenotypic differences, a taxonomic reassessment of the species is warranted. We performed a phylogenetic reconstruction using the mitochondrial genes ATPase 6/8 based on 33 samples from across the distribution of Red-fronted Tinkerbird and four outgroup samples, and then determined correspondence between genetic distances and differences in song and morphology among clades using the Tobias et al. criteria. Our phylogenetic analyses revealed 4.4% sequence divergence in mtDNA between northern and southern populations, with plumage, morphometric and song differences of a similar magnitude to those between P. pusillus and Yellow-fronted Tinkerbird P. chrysoconus, and above species-level thresholds according to the Tobias et al. criteria. Furthermore, the molecular phylogeny supports recognition of a synonymised taxon (P. p. eupterus) as a distinct, but phenotypically cryptic, subspecies in East Africa, with c.1.5% sequence divergence from P. p. affinis and P. p. uropygialis, which in turn differ less (1%) from each other. We propose that northern and southern Red-fronted Tinkerbirds are treated as separate species, and that the subspecies eupterus is resurrected. Our findings suggest that P. chrysoconus as presently constituted may also merit taxonomic revision.