Systematics Section / ASPT
Meudt, Heidi M. , Simpson, Beryl .
The biogeography of the austral, subalpine genus Ourisia (Plantaginaceae) based on molecular phylogenetic evidence: South American origin and dispersal to New Zealand and Tasmania.
Molecular phylogenetic analyses of 29 species, 4 subspecies and 2 purported natural hybrids of Ourisia (Plantaginaceae) are presented and used to examine the biogeography of the genus, which is distributed in subalpine to alpine habitats of South America, New Zealand and Tasmania. Gondwanan vicariance has often been cited as the cause of this classic austral biogeographic pattern. However, parametric bootstrapping of our combined dataset, which includes 2868 base pairs of nuclear (ITS and partial ETS) and chloroplast (matK 3’ intron and rps16 intron) DNA, rejects the Gondwana biogeographic hypothesis. Alternatively, various lines of evidence are presented in favor of a South American origin of Ourisia and subsequent dispersal to Australasia. Specifically, the genus likely arose in the Andes of central Chile and spread to southern Chile and Argentina. From there, Ourisia dispersed to the north-central Andes, and finally to Tasmania and New Zealand. The ancestor of the New Zealand species probably first arrived on the South Island, where the New Zealand species of Ourisia are most diverse, and migrated to the North and Stewart Islands. Because the Tasmanian and New Zealand species are sister to one another, the direction of dispersal between these two areas is equivocal. Our results agree with other molecular phylogenetic studies that show that past dispersal between Southern Hemisphere continents has played an important role in the evolutionary history of many high-elevation austral plants.
Home page of Heidi Meudt, with photos and information regarding Ourisia
1 - University of Texas at Austin, Plant Resources Center and Section of Integrative Biology, 1 University Station A6720, Austin, Texas, 78712, USA
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 10:00 AM