Systematics of the Cape legless skink Acontias meleagris species complex
Thesis (MSc)--Stellenbosch University, 2013.
This study examined the biogeography and taxonomic status of the Cape legless skink, Acontias meleagris species complex using phylogenetic analyses, population genetics, demographic history aspects, time of lineage diversification estimation, environmental statistic analyses and a morphological evaluation. A total of 231 specimens from 55 localities were collected from the entire known distribution range of the A. meleagris complex throughout the Eastern, Northern and Western Cape, South Africa. Partial sequence data were collected from two mitochondrial DNA loci, 16S rRNA and cytochrome oxidase subunit one (COI), and one protein-coding nuclear DNA locus, exophilin 5 (EXPH 5). DNA sequences were analyzed for phylogenetic methods and biogeographical dating, while population genetic analyses were conducted on the COI sequences. Geographical boundaries amongst cryptic lineages were determined and evolutionary drivers of cladogenesis within the species complex were inferred. Marked genetic structure was observed within the A. meleagris complex, and five clades were retrieved, most of which were statistically well supported. These five clades were also evident within the haplotypic analyses and were characterized by demographic stability. Lineage diversification and the current biogeographical patterning observed for lineages within the A. meleagris species complex reflect the impact of sea level oscillations on historical coastal habitat availability. Additional historical evolutionary drivers within this subterranean species complex were inferred and discussed. The five clades within this species complex were considered discrete species, characterised by phylogenetic and biogeographic distinctiveness. While, morphological characters that could be used to identify the five species demonstrated widespread overlap for morphometric and meristic characters as well as colour pattering. Consequently, the phylogenetic species concept was employed for a taxonomical revision of A. meleagris sensu lato. Here, three of the previously recognised subspecies A. m. meleagris, A. m. orientalis and A. m. orientalis–'lineicauda' were elevated to full species, and two new species A. caurinus sp. nov. and A. parilis sp. nov. were described.