Taxonomy and phylogeny of the family Fuscideaceae (Umbilicariales, Ascomycota) with special emphasis on Fuscidea

Introduction: For several decades, the taxonomic position of the lichen family Fuscideaceae and its associated genera, including the type genus Fuscidea V. Wirth & Vĕzda, has been debated. Amongst the species of Fuscidea, there are many questions about species limitation. The identity of the photobiont in Fuscidea is poorly known and has not been studied by molecular methods. To fill these gaps, the objectives of this thesis were the following: 1) Investigate the placement of Fuscideaceae within Ascomycota and to designate the genera to be included in this family (Paper I); 2) Examine the phylogenetic relationships within the genus Fuscidea (Paper I); 3) Elucidate the taxonomy of the F. lightfootii-F. pusilla species complex (Paper II); 4) Assess the infraspecific taxonomy of F. cyathoides (Ach.) V. Wirth & Vĕzda and the status of F. fagicola (Zschacke) Hafellner & Türk and F. stiriaca (A. Massal.) Hafellner (Paper III); 5) Identify the photobiont in Fuscidea and clarify its systematic placement (Paper IV). Methods: The concatenated data sets comprising the mitochondrial SSU and nuclear LSU, ITS rDNA regions of the fungal sequences (Papers I–III) as well as the individual 18S rDNA and partitioned ITS data sets of algal sequences (Paper IV) were analysed by Bayesian inference, maximum parsimony and maximum likelihood (ML) analysis. Principal Components Analysis (PCA) was used to assess selected morphological characters among varieties of F. cyathoides (Paper III). The ITS data set of algal sequences was run in the program Gblocks under relaxed and stringent masking to minimize the ambiguous positions in the alignment. The program SATé-II was used to analyse the non-aligned data matrix of ITS. The topologies and support values of the Bayesian and the ML trees recovered from the resulting aligned data sets were compared and their topologies with the ML tree calculated by SATé-II. The secondary structures of the ITS2 region were folded in order to identify Compensatory Base Changes (CBCs) and hemi-CBCs of the retrieved ITS groups (Paper IV). Results: Fuscideaceae included four genera and was located in Umbilicariales. The new genus Printzeniella Palice, Tønsberg & Zahradn. ined. was found to be closely related to Fuscidea. Ropalospora A. Massal. appeared as the first diverging lineage within Fuscideaceae and Maronea A. Massal. was nested within the Fuscidea-clade. The lichenicolous Lettauia D. Hawksw. & R. Sant. and Cryptodiscus Corda were nested in Stictidace