Phylogeography and speciation of lichens on a background of slow genetic drift and incomplete lineage sorting

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Lichens represent perfect models to investigate population history and speciation of fungi because they form well-delimited individual thalli. The distributional areas of fungi are mostly larger than those of vascular plants and intercontinental disjunctions are frequent. Our ongoing studies on population structure and speciation within lichens indicate that these distributional areas are the result of range fragmentation rather than long distance dispersal. Genetic drift is apparently slow and lineage sorting between closely related species often incomplete. This raises the question what role allopatric range fragmentation plays in lichen species formation. We will use multiple DNA sequences to investigate a group of morphologically similar lichens with a North American-European disjunction. Based on haplotype networks we want to resolve the phylogeography of the group and test whether lineage sorting between populations on different continents predates the formation of species. We will use Bayesian classification based on morphological attributes to separate our sample into classes and test the association between these Bayesian taxa and phylogenetic clades on haplotype networks.