Sequencing of the type species of Arthopyrenia places Arthopyreniaceae as a synonym of Trypetheliaceae

Abstract

Arthopyrenia sensu lato comprises lichenicolous, lichenized and non-lichenized saprotrophic species; however, the lifestyle of several taxa as either lichenized or saprotrophic remains unclear. The systematic position of the genus was so far unresolved: while sequenced species appeared in different clades within Dothideomycetes, the type species, A. cerasi, had no molecular data so far. In lieu of sequence data, the family Arthopyreniaceae was assigned to Pleosporales, whereas tropical, lichenized species were reclassified in Constrictolumina and Macroconstrictolumina, shown to belong in Trypetheliaceae (Trypetheliales). In this study, the generic type, A. cerasi, has been sequenced for the first time. Maximum likelihood and Bayesian phylogenetic analyses using mtSSU and nuLSU sequences recovered Arthopyrenia sensu stricto as an early diverging lineage within Trypetheliaceae, separate from Constrictolumina and Macroconstrictolumina but in the same clade as the temperate, non-lichenized Julella fallaciosa. Therefore, Arthopyreniaceae is here synonymized under Trypetheliaceae and the taxonomic placement of its type species is discussed based on morphological and phylogenetic evidence. Our phylogenetic results further support the polyphyly of non-lichenized, temperate species of Arthopyrenia and Julella sensu lato. Consequently, Julella fallaciosa is transferred to Arthopyrenia and its close relationship with A. cerasi is discussed. We also conducted ancestor character state analysis to reconstruct lifestyle changes within Trypetheliales using Bayes Traits and Bayesian Binary MCMC approaches.