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 Syrrhaptesnamaqua and S. gutturalis to have occurred at 25 Million years