Lichenicolous fungi of the genus Abrothallus (Dothideomycetes: Abrothallales ordo nov.) are sister to the predominantly aquatic Janhulales

This study provides new insights on the phylogenetic position of the lichenicolous fungal genus Abrothallus based on six molecular markers (nuSSU, nuLSU, mtSSU, RPB1, RPB2 and TEF-alpha). In a broad-scale analysis, we detected high support for inclusion of the genus within Dothideomycetes. A further analysis provided support for Abrothallus as a member of the subclass Pleosporomycetidae as a sister group of Jahnulales, an order of aquatic Dothideomycetes. Given the exclusive characters of this group of apotheciate fungi within the Dothidiomycetes, a new monotypic order Abrothallales is here introduced together with the new family Abrothallaceae. In a multi-locus analysis (based on the six loci indicated above plus ITS) restricted to 12 putative Abrothallus species, two clearly separated clades were observed: one comprising species growing on lichens of the families Parmeliaceae and Ramalinaceae, and the second including species that live on lichens of the order Peltigerales and the family Cladoniaceae.