Ptilopachinae: a new subfamily of the Odontophoridae (Aves: Galliformes).

The use of DNA sequences of diverse genetic loci has revolutionized our understanding of the systematic relationships among many different organisms. One such unexpected discovery was that two African galliform species, the Stone Partridge Ptilopachus petrosus Gmelin, 1789, and Nahan’s Francolin Francolinus nahani Dubois, 1905, represent a relictual clade sister to the New World Quail (Odontophoridae) and hence are only distantly related to other Old World Galliformes (Crowe et al. 2006, Cohen et al. 2012). Almost as unexpected was the recovery of the sister relationship between P. petrosus and F. nahani, which had never been considered close relatives, much less placed in the same genus (Crowe et al. 2006, Cohen et al. 2012). Previously unrecognized vocal and behavioral similarities between P. petrosus and P. nahani supported the genetic data and the transfer of nahani to Ptilopachus (Crowe et al. 2006, Cohen et al. 2012). Intriguingly, both species occupy areas suggested to serve both as centres of species diversification and places where relictual taxa persist (Kingdon 1989, Fjeldså & Bowie 2008, Fjeldså et al. 2012): P. nahani in dense primary forest in the vicinity of the Albertine Rift and P. petrosus in rocky outcrops of the Sahel. Cohen et al. (2012) suggested that the African Ptilopachus diverged from the New World quail some 37.4 Ma (95% HPD 31.7-43.0) in the Oligocene, and from each other some 9.6 Ma (95% HPD 5.8-14.0). Given the considerable time since Ptilopachus diverged from the remaining members of the Odontophoridae (genera Dendrortyx, Oreortyx, Callipepla, Philortyx, Colinus, Odontophorus, Dactylortyx, Cyrtonyx, and Rhynchortyx), as well as the clear disjunction of Old World taxa from New World taxa, we recommend that all New World species of Odontophoridae be placed in the subfamily Odontophorinae Gould, 1844, and in accordance with the International Code of Zoological Nomenclature (1999; Art. 13.1.1), erect and provide a formal definition below of a new subfamily to encompass the two African species of the genus Ptilopachus.