Molecular and morphological variation in a South African velvet worm Peripatopsis moseleyi (Onychophora, Peripatopsidae): evidence for cryptic speciation

The systematics of Peripatopsis moseleyi (Wood-Mason, 1879), a widely distributed South Africa velvet worm species, was examined to test the occurrence of cryptic lineages within this taxon. A total of 81 specimens of P. moseleyi were collected from 12 localities throughout its known distribution in the Eastern Cape and KwaZulu-Natal provinces of South Africa. All specimens were sequenced for a 631 bp fragment of the mitochondrial cytochrome oxidase one subunit (COI) locus, while a 717 bp pair fragment of the 18S rDNA locus was sequenced for a single sample for each of the clades evident from the COI topology. DNA sequence data were analysed using maximum parsimony and Bayesian inferences, while a haplotype network was constructed and an analysis of molecular variation was conducted. Gross morphological characteristics, such as the number of pre-genital leg pairs, the genital areas and colour variation in each sample locality were examined. Moreover, characters of the antennae, the shape of the main dermal papillae and male genital pad features were investigated. Topologies derived from the combined DNA analyses (COI and 18S rDNA) were congruent and revealed that P. moseleyi is a complex comprised of five genetically distinct clades. At present, these clades could not be differentiated based on morphological characters, suggesting that traditional species-discriminating characters have limited taxonomic utility. However, colour differences between the two sympatric morphs may be used to differentiate these clades. Our results indicate that cryptic speciation is present within P. moseleyi, with most of the novel detected lineages characterized by restricted geographic distribution.