The genus Ptilopachus was introduced in 1837 by the English naturalist William John Swainson to accommodate a single species, the stone partridge, which is therefore the type species.[2][3] The genus name is from Ancient Greekptilon meaning "feather" with pakhus meaning "thick" or "dense".[4]
As traditionally defined, only the stone partridge was included in this genus, but based on genetic evidence, it now also includes Nahan's partridge (formerly considered a francolin). The study also concludes that this genus is more closely related to the New World quails (Odontophoridae) and might be considered their only African representative.[5][6][7]
At about 25 cm (9.8 in) in length, both are relatively small, terrestrial birds with a red eye-ring, base of the bill, and legs, and brownish upperparts.[8]
^Cohen, C.; Wakeling, J.L.; Mandiwana-Neudani, T.G.; Sande, E.; Dranzoa, C.; Crowe, T.M.; Bowie, R.C.K. (2012). "Phylogenetic affinities of evolutionarily enigmatic African galliforms: the Stone partridge Ptilopachus petrosus and Nahan's francolin Francolinus nahani, and support for their sister relationship with New World quails". Ibis. 154 (4): 768–780. doi:10.1111/j.1474-919X.2012.01269.x.
^McGowan, P. J. K. (1994). Francolins (genus Francolinus). Pp. 489–504 in: del Hoyo, J., Elliott, A., & Sargatal, J. eds. (1994). Handbook of the Birds of the World. Vol. 2. New World Vultures to Guineafowl. Lynx Edicions, Barcelona. ISBN84-87334-15-6
