The phylogenetics of francolins (Francolinus species) were reassessed by obtaining 660 bp of sequence of the mitochondrial DNA (mtDNA) cytochrome b gene from 20 species, the Common Quail Coturnix coturnix africana, and the Madagascar Partridge Margaroperdix madagarensis. Published sequences of the Japanese Quail C. c. japonica, Alectoris partridges, and the Junglefowl Gallus gallus were also included. Separate analysis of the 200 phylogenetically informative cytochrome b characters and the 25 informative morphobehavioral characters, as well as a combined analysis of molecular and morphobehavioral data, do not support francolin monophyly but provide strong evidence for two previously suggested clades-the quail-francolins (or partridges) and the partridge-francolins (pheasants/ francolins). The quail-francolin clade comprises three groups of African francolins and three Asian species that were previously considered more closely related to the partridge-francolins. The partridge-francolin clade, which includes four groups of African francolins, forms a sister group to the Coturnix quails, the Madagascar Partridge, and the Alectoris partridges. The molecular data suggest that the two francolin clades diverged approximately 3-6 MYA. Climatic fluctuations of the past 2.5 MYA may have led to the diversification of the ecologically different francolin species groups and speciation within them. (C) 1998 Academic Press.