Species boundaries and conservation of the velvet worm genus Peripatopsis in South Africa
Date
2016-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: This study examined biogeographical and taxonomic relationships within the genus Peripatopsis
with a special emphasis on the Peripatopsis capensis species complex using phylogenetic analyses,
population genetics, divergence time estimation, ancestral area reconstruction, scanning electron
microscopy, and gross morphological analysis. A total of 104 specimens were collected from 21
localities from the known distribution of the Peripatopsis capensis species complex in the Western
Cape, 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 gene
fragments were selected for this study, namely the mitochondrial DNA cytochrome c oxidase one
subunit (COI) and the 18S rRNA nuclear DNA gene locus. DNA sequences were analysed using
phylogenetic methods and divergence time dating. The P. capensis species complex population
genetic analyses were conducted on COI, while ancestral area inference for Peripatopsis was
carried out using COI and 18S. For the P. capensis species complex geographic boundaries amongst
cryptic lineages were inferred using Phylogeobuilder and evolutionary drivers of cladogenesis were
determined for the latter as well as for the genus. A conservation assessment was carried out on
described species using the IUCN red list framework and phylogenetic diversity indexes.
Phylogenetic analysis reveals that P. capensis is a species complex comprised three geographically
discrete and statistically well supported clades. Peripatopsis was retrieved as a genus comprising 12
statistically well supported and taxonomically described species, with three species being retrieved
as non-monophyletic. Divergence time analysis results revealed Plio/Pleistocene diversification for
the P. capensis species complex and an early Miocene diversification for the Peripatopsis genus
coincident with climatic amelioration during the time period. The ancestor of the latter originated in
the geomorphic province delineated as the Syntaxis Cape Fold Mountain region. While gross
morphological characters for P. capensis such as leg pair number was invariant, scanning electron
microscopy (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 the
IUCN framework all described species within the Peripatopsis genus require red listing and
phylogenetic diversity indexes have highlighted the Cape Peninsula and the Central Cape Fold
mountains as regions with a rich evolutionary history and high evolutionary potential.
AFRIKAANS OPSOMMING: Geen opsomming beskikbaar.
AFRIKAANS OPSOMMING: Geen opsomming beskikbaar.
Description
Thesis (MSc)--Stellenbosch University, 2016.
Keywords
Velvet worm (Peripatopsis capensis), Peripatopsis capensis -- Biogeography, Phylogenetic analysis -- Peripatopsis capensis, Peripatopsis capensis -- Conservation, UCTD