Phylogenetics and biogeography of the relhanioid paper-daisy lineage (Asteraceae: Gnaphalieae) : palaeoenvironmental evolution, migration and speciation in southern Africa and the greater Afrotemperate regions

The true circumscription and subtribal division of Gnaphalieae is currently not known, and a series of recent molecular phylogenetic analyses have indicated that the previously-accepted subtribal delimitation of Anderberg (1991) comprises non-monophyletic entities (Bayer et al. 2000; Bergh & Linder 2009; Ward et al. 2009). Anderberg's (1991) morphological parsimony analysis identified five subtribes, including the largely southern African subtribe Relhaniinae, considered by Linder (2003) to be the tenth-largest “Cape Floral Clade”, as well as a non-classified group of taxa which he considered putatively “basal” to Gnaphalieae. A subsequent molecular analysis (Bayer et al. 2000) indicated that many of the taxa from Anderberg's (1991) subtribe Relhaniinae and the southern African members of the “basal taxa” constitute a single lineage. This lineage, termed the “Relhania clade” by Bergh & Linder (2009), is identified by several studies as the earliest-diverging lineage in Gnaphalieae (Bayer et al. 2000; Bergh & Linder 2009; Ward et al. 2009). The Relhania clade (whose members will hereafter also be referred to as “relhanioid” taxa) forms the focus of this thesis. To date, only placeholder representatives of relhanioid species have been represented in phylogenetic analyses (Bayer et al. 2000; Bergh & Linder 2009; Klaassen & Bergh 2012; Montes-Moreno et al. 2010; Smissen et al. 2011; Ward et al. 2009); thus the Relhania clade as currently defined comprises only 24 species. On morphological grounds, the following taxa are likely to be relhanioid: Antithrixia (monotypic), Arrowsmithia (monotypic), Athrixia (14 sp.), Comborhiza (ditypic), Leysera (3 sp.), Macowania (12 sp.), Nestlera (monotypic), Oedera (18 sp.), Oreoleysera (monotypic), Pentatrichia 4 (6 sp.), Phagnalon (41 sp.; three of which are subspecific), Relhania (13 sp.), Rhynchopsidium (2 sp.) and Rosenia (4 sp.). If all these taxa are confirmed to be members of the Relhania clade, the group will comprise a total of 119 species in 14 genera. Two further genera, Alatoseta (monotypic) and Philyrophyllum (ditypic) are believed to be closely-related to, if not members of, the Relhania clade (Anderberg 1991; Montes-Moreno et al. 2010) although they are morphologically anomalous taxa whose relationships are poorly understood.

Grantor dc:publisher.institution

Department of Biological Sciences

Year dc:date.issued

2014

Author dc:creator

• Bentley, Joanne

Advisors dc:contributor.advisor

• Verboom, Tony
• Bergh, Nicola

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/9190

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/9190