Cryptic subterranean diversity: regional phylogeography of the sand termite Psammotermes allocerus Silvestri, 1908 in the wider Namib region

Abstract

Psammotermes allocerus Silvestri, 1908 is the only described species representing the genus Psammotermes Desneux, 1902 in Southern Africa. The large geographical range of this subterranean termite covers both summer and winter rainfall regimes. Deadwood is the preferred food when available, but in more arid habitats, both live and dead grasses form the major dietary component. Along the Namib Desert margins, the species’ localised herbivory creates circular bare patches known as fairy circles. For a regional phylogeographic study of this species, we sampled 65 sand termite populations within drier parts of Namibia, South Africa, and Angola. Based on combined molecular and ecological data, we found considerable genetic diversification within P. allocerus. Analyses of two mitochondrial markers (COI, COII), including a Bayesian inference tree, haplotype analysis and genetic distances suggest a delineation into seven highly differentiated genetic groups. The ‘Succulent Karoo’ group is additionally characterised by unique features of the royal chamber, nest and tunnel system. In conclusion, our data suggest that P. allocerus should be not regarded as one species but as a species complex. Termites of each analysed group ‘Northern Namib’, ‘Western Kalahari Basin’, ‘Nama’, ‘Southwestern Kalahari’, ‘East Gariep’, ‘Southern Namib’ and ‘Succulent Karoo’ should be considered as distinct species. The species name P. allocerus should be used for termites of the ‘Succulent Karoo’.