Major clades and phylogenetic relationships between lichenized and non-lichenized lineages in Ostropales (Ascomycota: Lecanoromycetes)

The fungal order Ostropales is unique in Ascomycota for including both lichen-forming and non-lichenized species and species with optional nutritional strategies depending on substrate. To address the phylogenetic relationships within the order, we assembled a dataset of 78 ostropalean species, including all major clades and 23 taxa that are only optionally lichenized or non-lichenized. The analyses are based on sequences of the mtSSU and nuLSU rDNA and the protein-coding gene RPB2. A close relationship of Graphidaceae and Gomphillaceae is suggested with the latter possibly nested within Graphidaceae. Odontotremataceae is composed of two distantly related groups. Coenogoniaceae and Porinaceae are sister taxa, and their relation to Gyalectaceae is unresolved. Gyalecta is paraphyletic with Belonia and Pachyphiale nested within. A polyphyletic Belonia indicates that perithecioid ascomata evolved more than once in Gyalectaceae. The new family Sagiolechiaceae is proposed to accommodate Rhexophiale and Sagiolechia and Solorinellaceae is reinstated distinct from Gomphillaceae. Belonia and Pachyphiale are reduced to synonymy with Gyalecta. The distribution of phenotypical character states is discussed with selected character states mapped onto a phylogenetic tree. A special focus is given on lifestyles. Our phylogeny suggests that there is more plasticity in the evolution of life-styles in these fungi than was previously assumed.