A reappraisal of orders and families within the subclass Chaetothyriomycetidae (Eurotiomycetes, Ascomycota)

The subclass Chaetothyriomycetidae (Eurotiomycetes, Ascomycota) is an assemblage of ecologically diverse species, ranging from mutualistic lichenised fungi to human opportunistic pathogens. Recent contributions from molecular studies have changed our understanding of the composition of this subclass. Among others, ant-associated fungi, deep-sea fungi and bryophilous fungi were also shown to belong to this group of ascomycetes. The delimitation of orders and families within this subclass has not previously been re-assessed using a broad phylogenetic study and the phylogenetic position of some taxa such as the lichenised family Celotheliaceae or the Chaetothyrialean bryophilous fungi is still unclear. In our study, we assemble new and published sequences from 132 taxa and reconstruct phylogenetic relationships using four markers (nuLSU, nuSSU, mtSSU and RPB1). Results highlight several shortfalls in the current classification of this subclass, mainly due to un-assigned paraphyletic taxa. The family Epibryaceae is therefore described to circumscribe a previously un-assigned lineage. Celotheliales ad int. is suggested for the lineage including the lichen genus Celothelium and various plant pathogens. The delimitation of the family Trichomeriaceae is also broadened to include the genus Knufia and some anamorphic taxa. As defined here, Chaetothyriomycetidae includes four orders (Celotheliales ad int., Chaetothyriales, Pyrenulales, and Verrucariales) and ten families (Adelococcaceae, Celotheliaceae, Chaetothyriaceae, Cyphellophoraceae, Epibryaceae fam. nov., Herpotrichiellaceae, Pyrenulaceae, Requienellaceae, Trichomeriaceae, and Verrucariaceae).