Species boundaries and conservation of the velvet worm genus Peripatopsis in South Africa

[摘要] ENGLISH ABSTRACT: This study examined biogeographical and taxonomic relationships within the genus Peripatopsiswith a special emphasis on the Peripatopsis capensis species complex using phylogenetic analyses,population genetics, divergence time estimation, ancestral area reconstruction, scanning electronmicroscopy, and gross morphological analysis. A total of 104 specimens were collected from 21localities from the known distribution of the Peripatopsis capensis species complex in the WesternCape, while 54 specimens from prior studies on the Peripatopsis genus from the Western Cape,Eastern Cape, and KwaZulu-Natal were used for the analysis of the genus. Two partial genefragments were selected for this study, namely the mitochondrial DNA cytochrome c oxidase onesubunit (COI) and the 18S rRNA nuclear DNA gene locus. DNA sequences were analysed usingphylogenetic methods and divergence time dating. The P. capensis species complex populationgenetic analyses were conducted on COI, while ancestral area inference for Peripatopsis wascarried out using COI and 18S. For the P. capensis species complex geographic boundaries amongstcryptic lineages were inferred using Phylogeobuilder and evolutionary drivers of cladogenesis weredetermined for the latter as well as for the genus. A conservation assessment was carried out ondescribed species using the IUCN red list framework and phylogenetic diversity indexes.Phylogenetic analysis reveals that P. capensis is a species complex comprised three geographicallydiscrete and statistically well supported clades. Peripatopsis was retrieved as a genus comprising 12statistically well supported and taxonomically described species, with three species being retrievedas non-monophyletic. Divergence time analysis results revealed Plio/Pleistocene diversification forthe P. capensis species complex and an early Miocene diversification for the Peripatopsis genuscoincident with climatic amelioration during the time period. The ancestor of the latter originated inthe geomorphic province delineated as the Syntaxis Cape Fold Mountain region. While grossmorphological characters for P. capensis such as leg pair number was invariant, scanning electronmicroscopy (SEM) yielded differentiating characters, albeit limited (e.g. dermal papillae and male genital pads). Two new Peripatopsis species are described in the present study. According to theIUCN framework all described species within the Peripatopsis genus require red listing andphylogenetic diversity indexes have highlighted the Cape Peninsula and the Central Cape Foldmountains as regions with a rich evolutionary history and high evolutionary potential.

[发布机构] Stellenbosch University