Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes

Simple item page
dc.contributor.advisorVerboom, George Anthonyen_ZA
dc.contributor.advisorHedderson, Terry Aen_ZA
dc.contributor.authorHenning, Jacken_ZA
dc.date.accessioned2014-09-08T09:57:02Z
dc.date.available2014-09-08T09:57:02Z
dc.date.issued2003en_ZA
dc.descriptionBibliography: leaves 84-100.en_ZA
dc.description.abstractA phylogeny was produced for the eight taxa comprising the largely South African genus Melianthus L. based on two plastid markers (trnL-F and psbA-trnH) and one nuclear marker (ITS). Topological comparisons with a tree based on an existing morphological data set revealed significant incongruence leading to a loss of resolution upon combination. Ultimately, the combined three-gene data tree was selected as the strongest phylogenetic estimate for Melianthus based on its better resolution and greater support levels. This tree confirms the monophyly of Melianthus with M. major being resolved as sister to the remainder of the genus. Within the remaining clade, M. villosus is resolved sister to a clade comprising two morphologically distinct subclades, one of these being noted for a western distribution (comprising M. elongatus and the M. pectinatus complex), the other being centred farther east (comprising M. cocomosus and the M dregeanus complex). A molecular clock analysis was employed to date the emergence of specific taxa and clades, while ancestral range and habitat reconstructions were performed to determine historical conditions under which these groups and their morphological novelties arose. A scenario depicting the evolution and diversification of Melianthus is developed against a backdrop of the paleo-history of southern Africa. The genus appears to have originated in the eastern part of South Africa during a mild, mesic Oligocene with subsequent westward expansion into drier habitats of Miocene and Pliocene origins. Observations of bird visitors to a range of Melianthus species indicate that the genus employs a generalist pollination syndrome, thus refuting suggestions of a co-exclusive relationship with sunbirds (Nectariniidae). Nevertheless, the genus is undeniably ornithophilous. Nectar studies reveal interspecific variation in both the volume and concentration of nectar produced as well as in nectar colourition.en_ZA
dc.identifier.apacitationHenning, J. (2003). <i>Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/6971en_ZA
dc.identifier.chicagocitationHenning, Jack. <i>"Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2003. http://hdl.handle.net/11427/6971en_ZA
dc.identifier.citationHenning, J. 2003. Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Henning, Jack AB - A phylogeny was produced for the eight taxa comprising the largely South African genus Melianthus L. based on two plastid markers (trnL-F and psbA-trnH) and one nuclear marker (ITS). Topological comparisons with a tree based on an existing morphological data set revealed significant incongruence leading to a loss of resolution upon combination. Ultimately, the combined three-gene data tree was selected as the strongest phylogenetic estimate for Melianthus based on its better resolution and greater support levels. This tree confirms the monophyly of Melianthus with M. major being resolved as sister to the remainder of the genus. Within the remaining clade, M. villosus is resolved sister to a clade comprising two morphologically distinct subclades, one of these being noted for a western distribution (comprising M. elongatus and the M. pectinatus complex), the other being centred farther east (comprising M. cocomosus and the M dregeanus complex). A molecular clock analysis was employed to date the emergence of specific taxa and clades, while ancestral range and habitat reconstructions were performed to determine historical conditions under which these groups and their morphological novelties arose. A scenario depicting the evolution and diversification of Melianthus is developed against a backdrop of the paleo-history of southern Africa. The genus appears to have originated in the eastern part of South Africa during a mild, mesic Oligocene with subsequent westward expansion into drier habitats of Miocene and Pliocene origins. Observations of bird visitors to a range of Melianthus species indicate that the genus employs a generalist pollination syndrome, thus refuting suggestions of a co-exclusive relationship with sunbirds (Nectariniidae). Nevertheless, the genus is undeniably ornithophilous. Nectar studies reveal interspecific variation in both the volume and concentration of nectar produced as well as in nectar colourition. DA - 2003 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2003 T1 - Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes TI - Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes UR - http://hdl.handle.net/11427/6971 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/6971
dc.identifier.vancouvercitationHenning J. Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2003 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/6971en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherSystematics and Biodiversity Sciencesen_ZA
dc.titleFurther studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_2003_henning_j.pdf
Size:
6.93 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters