Pterocliformes
This order is represented by the family Pteroclidae (sandgrouse) only.
Species-level phylogeny of extant Pteroclidae based on Cohen (2011), with the distribution of each species being indicated by the colour-code used throughout this
website (see Distribution code). A dated phylogeny is not yet available, but Soares et al. (2016) consider the divergence between
Syrrhaptes namaqua and S. gutturalis to have occurred at 25 Million years
ago.
References/Literature
Cohen C (2011), The phylogenetics, taxonomy and biogeography of African arid zone terrestrial birds: the bustards (Otididae), sandgrouse (Pteroclidae), coursers (Glareolidae) and Stone Partridge (Ptilopachus), Ph.D. Dissertation, University of Cape Town. (pdf)
Soares AER, Novak BJ, Haile J, Heupink TH, Fjeldsa J, Gilbert MTP, Poinar H, Church GM, and Shapira B (2016), Complete mitochondrial genomes of living and extinct pigeons revise the timing of the columbiform radiation, BMC Evol. Biol. 16: 230. (pdf)