An evaluation of genetic structuring and morphometric variation within tusked king crickets, Libanasidus vittatus (Kirby, 1899), from South Africa suggests two main population assemblages. Maximum likelihood (ML), Parsimony, Bayesian and phenetic analyses of mitochondrial cytochrome oxidase I (COI) sequence data recovered two well-supported clades corresponding to two biogeographically distinct populations. Canonical variates (discriminant) analysis (CVA) also showed evidence of two phenetic assemblages that correspond to the genetically delineated groups. Libanasidus vittatus is the recognized species occurring within an eastern population in South Africa (Mpumalanga and Eastern Cape Provinces), while a possible novel species occurs within a north–western population in South Africa (Limpopo and Gauteng Provinces). Using a molecular clock estimate of 2.0% divergence per million years, suggests isolation of the two populations at approx. 1.65 million years ago, possibly due to the formation of isolating forest pockets during the dry Pleistocene Epoch. The average genetic divergence of 3.3% between the two populations, and low migration rate estimates corresponding to less than one female migration per generation further support the presence of two cryptic tusked king cricket species in South Africa.