| Abstract Detail
Systematics Section / ASPT Pelser, Pieter B. [1], Tepe, Eric J. [1], Kennedy, Aaron H. [1], Marticorena, Alicia [2], Arroyo, Mary T. K. [3], Watson, Linda E. [1]. Mediterranean diversifications in Tribe Senecioneae (Asteraceae). Senecioneae is one of the largest tribes of Asteraceae, comprised of approximately 150 genera and 3000 species. It has an almost cosmopolitan distribution and harbours enormous diversity in life-history strategies and morphological adaptations. Senecioneae is well represented in areas with a mediterranean climate, and is one of few plant groups that have representatives in all five mediterranean regions of the World (the Mediterranean Basin, California Floristic Province, central Chile, Cape Province of South Africa, and southwestern Australia). To determine whether the origin of mediterranean climates has been an important factor in the diversification of the tribe, we are examining lineages of Senecioneae in all five mediterranean regions using phylogenetic and biogeographic techniques. A molecular phylogeny of the tribe, including representatives of 114 genera and 614 species, reveals clear biogeographic patterns. Lineages which occur in these mediterranean-climates are present in various parts of the tree, but are concentrated in subtribes Othonninae and Senecioninae – both of which originated in sub-Saharan Africa. Senecio is the only genus in the tribe present in all five mediterranean areas, and in general, species in mediterranean climate zones are found in relatively few clades that also include species from neighbouring geographical areas. A pilot study focussing on central Chile showed that most Chilean Senecio species are found in two major clades, both of which contain mediterranean species. One of these clades most likely originated in southern Chile. The other clade is composed of species growing in various parts of Andean southern South America. Phylogenetic relationships are poorly resolved within this latter clade due to low sequence variation in the ITS and ETS regions. This is in sharp contrast to wide morphological variation in this clade, and perhaps indicates recent adaptive radiation in central Chile.
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http://pieterpelser.blogspot.com/
1 - Miami University, Department of Botany, Oxford, Ohio, 45056, USA
2 - Universidad de Concepción, Facultad de Ciencias Naturales y Oceanográf, Departamento de Botánica, Casilla 160-C, Concepción, Chile
3 - Institute of Ecology and Biodiversity (IEB), Universidad de Chile, Casilla 653, Santiago, Chile
Keywords:
Biogeography
molecular phylogenetics
radiation.
Presentation Type: Poster:Posters for Sections
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P59042
Abstract ID:1261 |
