Molecular evidence for cryptic species in the common slug eating snake duberria lutrix lutrix (Squamata, Lamprophiidae) from South Africa

Abstract

We examined the impact of climatic fluctuations on the phylogeographic structure of the common slug eating snake (Duberria lutrix lutrix) throughout its distribution in South Africa. The evolutionary history within the taxon was examined using partial DNA sequence data for two mitochondrial genes (ND4 + cyt b) in combination with a nuclear locus (SPTBN1). Phylogenetic relationships were investigated for both the combined mtDNA and total evidence DNA sequence data. In addition, population and demographic analyses together with divergence time estimations were conducted on the combined mtDNA data. Topologies derived from the combined mtDNA analyses and the total evidence analyses were congruent and retrieved five statistically well-supported clades, suggesting that Duberria l. lutrix represents a species complex. The five clades were generally allopatric, separated by altitudinal barriers and characterised by the absence of shared mtDNA haplotypes suggesting long term isolation. Divergence time estimations indicate that the diversification within the D. l. lutrix species complex occurred during the Plio/Pleistocene as a result of climatic fluctuations and habitat shifts for the species. A taxonomic revision of the D. l. lutrix species complex may be required to delineate possible species boundaries.