Recent proposed changes to the taxonomy of spurfowl and francolins: further commentary and concerns

A recent taxonomic revision of African spurfowl and francolins (family Phasianidae) proposed to recognise 16 new species. The authors suggested that divergence in cytochrome-b (CYTB) of >1.5% is sufficient to recognise taxa as species. Their molecular material was obtained mainly from museum specimens. However, the study contained errors with some registration numbers and identifications as recorded on specimen labels, and assumptions were made concerning some taxa for which no museum specimens were examined. Given that CYTB sequences among three specimens of the same taxon from the same location and population were divergent by 8%, their framework for delineating species in this group must be considered highly questionable. Other CYTB divergence between taxa ranked as subspecies of the same taxon by the authors of the study were mostly >1.5%, further undermining their hypothesis, and some CYTB data appear to have been selectively excluded. Zero CYTB sequence divergence between geographically distant subspecies suggests interbreeding between them and undermines the assumption that there is none (or it is limited), which was one of the criteria they used to separate species. In addition, existing distributional data were misinterpreted or overlooked, and their own taxonomic decisions were omitted from their updated distribution maps thereby compounding errors already resulting from a misinterpretation of regional distributional data. Brief morphological descriptions were also provided, but not all taxa of some species were examined and sexual plumage dimorphism for others was ignored, producing some significant errors. Consequently, I conclude that these proposed new species should be rejected in the absence of further and more robust evidence.