Authors:	Messerschmid, Thibaud Felix Edmond
Advisor:	Kadereit, Joachim W.
Title:	Phylogenetics and Evolution of Crassulaceae subf. Sempervivoideae
Online publication date:	3-Mar-2022
Year of first publication:	2022
Language:	english
Abstract:	The Crassulaceae are a family of leaf succulent plants comprising about 1410 species, with centres of diversity in South Africa and Mexico, but with similarly high diversity and floristic importance in Macaronesia. The Crassulaceae can be divided into three subfamilies, each characterized as monophyletic and morphologically distinct lineages. While the South African diversity centre exclusively hosts representatives of the subfamilies Crassuloideae and Kalanchoideae, the most species-rich subfamily Sempervivoideae has its distribution focus in the Northern Hemisphere. Previous phylogenetic studies in the Crassulaceae have identified a sister relationship of Sempervivoideae and Kalanchoideae, as well as five supported major clades within Sempervivoideae. Among several other genera, Sedum is represented in three of these five clades, making Sedum a non-monophyletic genus. Two chapters of this dissertation deal with the molecular phylogenetics of Sedum and related genera and aim at making monophyletic and morphologically definable lineages the basis of a proposed generic classification of the Sempervivoideae. In addition to these questions of systematics and classification, the phylogenetic analyses presented here have also served to answer biogeographical and evolutionary biological questions, such as the mechanisms and consequences of diversification. The most important conclusion from the first study, a molecular phylogenetic investigation of the entire subfamily Sempervivoideae, is firstly the proposal to transfer all 14 currently accepted genera of the phylogenetically well-supported tribe Sedeae into Sedum. With this option, common morphological descriptions of Sedum found in the literature can essentially remain unaltered. Secondly, this study was able to show that migrations from the ancestral range (probably the area of the former Tethys and Paratethys) had repeatedly led to increased morphological diversification in the evolution of the Sempervivoideae, which in taxonomic history has led to the description of several genera besides Sedum, especially for the American and Asian taxa. The object of the second and third study was tribe Aeonieae, which contains the most species-rich plant radiation of the Macaronesian Islands, the Aeonium alliance comprising Aeonium, Aichryson and Monanthes. Using a next-generation sequencing approach, I was able to contribute to a well-resolved phylogeny and biogeography of all 40 Aeonium species. It could be shown that sympatric diversification events had led to a more pronounced morphological and partly ecological divergence of the sister groups than allopatric diversification events had. Finally, the third study dealt with the mainly Northwest African Sedum species of tribe Aeonieae, which for the first time included all relevant Sedum species of the Aeonieae in a molecular phylogenetic analysis. This allowed me to identify the possibly closest relatives of the above-mentioned Macaronesian genera and to discuss a possible concept for a genus classification in the Aeonieae.
DDC:	500 Naturwissenschaften 500 Natural sciences and mathematics 570 Biowissenschaften 570 Life sciences 580 Pflanzen (Botanik) 580 Botanical sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 10 Biologie
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-6756
URN:	urn:nbn:de:hebis:77-openscience-76838753-9b16-48a5-920d-049637f9b7009
Version:	Original work
Publication type:	Dissertation
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Extent:	164 Seiten, Illustrationen, Diagramme
Appears in collections:	JGU-Publikationen