Evidence of cryptic speciation in mesostigmatid mites from South Africa

Abstract

Laelaps giganteus and Laelaps muricola (Mesostigmata; Laelapidae) are widespread and locally abundant host generalists on small mammals in southern Africa. The large host range and complex life history of these ectoparasites may allude to possible intraspecific cryptic diversity in these taxa. To assess genetic and morphological diversity in L. giganteus and L. muricola, we sampled 228 rodents at eight localities in South Africa. This sample included nine previously recorded host species and on these, L. muricola was only recorded from Mastomys natalensis and Micaelamys namaquensis while L. giganteus was found on Rhabdomys dilectus and Lemniscomys rosalia. Phylogenetic analyses of partial mtDNA cytochrome oxidase subunit I (COI) and nuclear ITS1 data strongly supported the recognition of L. giganteus and L. muricola, a scenario partly supported by the Tropomyosin intron. Strong support for evolutionary distinct lineages within L. giganteus is found: L. giganteus lineage 1 is confined to R. dilectus and L. giganteus lineage 2 is confined to L. rosalia. These host specific monophyletic lineages were also separated by 9-84% mtDNA sequence divergence and 3-44% nuclear DNA sequence divergence. Since quantitative morphometric analyses were not congruent with these findings, these two lineages more than likely represent cryptic species.