Phylogeny of the Acarosporaceae (Lecanoromycetes, Ascomycota, Fungi) and the evolution of carbonized ascomata

The phylogeny of the Acarosporaceae (Lecanoromycetes, Acarosporomycetidae, Acarosporales) is investigated using data from three molecular markers; nuclear ITS-LSU rDNA, mitochondrial SSU and β-tubulin. Acarosporaceae is shown to be constituted by six main clades; Myriospora, Timdalia, Pleopsidium, a clade composed by “Acarospora” rhizobola and “A.” terricola, the poorly supported Sarcogyne clade (including several Polysporina and Acarospora species) and the Acarospora clade (including the type of Polysporina, P. simplex, and several other Polysporina species). The common ancestor of the Acarosporaceae did not produce strongly black pigmented (carbonized or melanized) ascomata, but this trait has arisen secondarily and independently numerous times in the evolution of the group. The number of changes in character states of both carbonized epihymenium and carbonized exciple are considerably more than the minimum number. The genera Sarcogyne and Polysporina—largely circumscribed based on the presence of black pigmented ascomata—are shown to be distinctly non-monophyletic. The presence of green algae in the ascoma margin (lecanorine or lecideine ascomata) may vary even within single species.