Browsing by Author "Engelbrecht, Hanlie M."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Exploration into the hidden world of Mozambique's sky island forests : new discoveries of reptiles and amphibians
    (Pensoft, 2016) Conradie, Werner; Bittencourt-Silva, Gabriela B.; Engelbrecht, Hanlie M.; Loader, Simon P.; Menegon, Michele; Nanvonamuquitxo, Cristovao; Scott, Michael; Tolley, Krystal A.
    We carried out a survey of reptiles and amphibians within Afromontane forest and woodland slopes of three inselbergs in northern Mozambique (Mount Mabu, Mount Namuli, and Mount Ribáuè). A total of 56 species (22 amphibians and 34 reptiles) were recorded during the current survey. Our findings substantially increase the number of herpetofaunal species recorded from these mountains (Mount Ribáuè 59%, Mount Mabu 37%, and Mount Namuli 11% of the total species), including one new country record and several putative new species. An updated checklist of the herpetofauna of these mountains is presented.
  • Thumbnail Image
    Item
    The radiation and biogeography of snakes across south-eastern Africa with respect to the evolution of the savanna biome
    (Stellenbosch : Stellenbosch University, 2017-12) Engelbrecht, Hanlie M.; Tolley, Krystal A.; Mouton, P. L. N.; Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology.
    ENGLISH ABSTRACT: The heterogeneous landscape of the African continent was preceded by a pan-African forest that has been transformed by concomitant contractions and expansions of this biome since the Oligocene epoch, to primarily savanna at present. As such, faunal groups that emerged during the Paleogene/Neogene period and have species distributed in both forest and savanna habitat should show a genetic signature of the possible evolutionary impact of these biome developments. Crotaphopeltis and Philothamnus were ideal candidate taxa to investigate the evolutionary impact of these biome developments on widespread African colubrid snakes. Species in these two genera occur throughout sub-Saharan Africa and are associated with either closed (forest), open (e.g. savanna), as well as both habitat types. The main research aim was to investigate synchronised timing and patterns of radiation for Crotaphopeltis and Philothamnus with respect to these African biome developments. Knowledge of the evolutionary relationships for the two genera was needed to construct their biogeographic histories reliably. Therefore, described species of Crotaphopeltis and Philothamnus were investigated for their validity under the Evolutionary Species Concept with an aim to identify cryptic species that are otherwise masked by phenotypic and/or ecological parallels. Newly identified species were used in subsequent analysis of timing of lineage diversification and the reconstruction of ancestral habitat states. The influence of historical environmental conditions on the evolution of the climatic niche of two wide-ranging species in each of the genera, C. hotamboeia and P. angolensis were additionally studied. The climatic distributions of the two species were modelled for contrasting climatic conditions during the Pleistocene period and their ancestral climatic states were reconstructed. Results show that both genera are monophyletic. Up to seven candidate species are recognised within Philothamnus and two within Crotaphopeltis, which provide a basis for future taxonomic revisions. Timing of lineage diversification and associated shifts of species into novel habitats correspond to the historical developments of the forest and savanna biomes, since the Oligocene. Philothamnus showed an ancestral preference toward closed habitat, while the ancestral habitat type for Crotaphopeltis was equivocal between closed and open habitat types. The Miocene epoch signifies a period of increased diversity within both genera. It specifically appears that the climatic oscillations during Early/Mid-Miocene facilitated the evolution of C. hotamboeia as a climatic generalist, whilst the Late-Miocene climatic conditions induced specialisation of P. angolensis in subtropical climate. The research presented here demonstrates that development of habitat throughout the Late Oligocene influenced the radiation patterns of the colubrid snake genera, Crotaphopeltis and Philothamnus.
  • Thumbnail Image
    Item
    Systematics of the Cape legless skink Acontias meleagris species complex
    (Stellenbosch : Stellenbosch University, 2013-03) Engelbrecht, Hanlie M.; Daniels, Savel R.; Heideman, Neil J. L.; Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology.
    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.