The Red-billed Francolin is an endemic species of the northern aspects of the South West Arid Zone of the Afrotropics, which ranges from central and northern Namibia (south as far as c. 27°S) and southwestern Angola, east to the mid-Zambezi R. drainage in southwestern Zambia and northwestern Zimbabwe, being replaced to its immediate east by a closely allied congener in the form of the Natal Francolin, and to the south of its range in the west by the larger Cape Francolin. In their recent major revisionary study of the francolins, Crowe et al. (1992) group these three so-called partridge-francolins, following the generic recommendations of both Hall (1963) and Wolters (1976), along with a fourth species (Hildebrandt’s Francolin), in the new subgenus Notocolinus in the resurrected genus Pternistis Wagler, 1832, the types of both being the Cape Francolin Tetrao capensis Gmelin, 1789. Crowe (1993) validated the introduction of the name Notocolinus, thereby becoming its sole author, as well as of three other subgenera of francolins proposed at the same time. It is worthwhile noting that as far back as 1934 Peters, in his Check-List, recognised the desirability of separating Pternistis from Francolinus Stephens, 1819, but inadvertently left its type-species four-square in the latter genus. Francolinus has as its genotype Tetrao francolinus = Francolinus francolinus (Linnaeus), a polytypic species of the southwestern Palaearctic and the Indian Sub-Region.