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

 

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dc.contributor.advisor Verboom, George Anthony en_ZA
dc.contributor.advisor Hedderson, Terry A en_ZA
dc.contributor.author Henning, Jack en_ZA
dc.date.accessioned 2014-09-08T09:57:02Z
dc.date.available 2014-09-08T09:57:02Z
dc.date.issued 2003 en_ZA
dc.identifier.citation Henning, 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.uri http://hdl.handle.net/11427/6971
dc.description Bibliography: leaves 84-100. en_ZA
dc.description.abstract 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. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Systematics and Biodiversity Sciences en_ZA
dc.title Further studies with Melianthus L. : a molecular phylogeny, evolutionary patterns of diversification in the genus and pollinator syndromes en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Henning, 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/11427/6971 en_ZA
dc.identifier.chicagocitation Henning, 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/11427/6971 en_ZA
dc.identifier.vancouvercitation Henning 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/11427/6971 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


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