This order is represented by the family Pteroclidae (sandgrouse) only.
Phylogeny of Pteroclidae based on Cohen (2011), with the distribution of each species being indicated by the colour-code used throughout this
website (see Distribution colour 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
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, A.E.R. et al. (2016), Complete mitochondrial genomes of living and extinct pigeons revise the timing of the columbiform radiation, BMC
Evolutionary Biology, 16: 230. (pdf)