Phylogenetic insights resolve Dacampiaceae (Pleosporales) as polyphyletic: Didymocyrtis (Pleosporales, Phaeosphaeriaceae) with Phoma-like anamorphs resurrected and segregated from Polycoccum (Trypetheliales, Polycoccaceae fam. nov.)

A phylogenetic analysis of nuLSU and ITS sequences representing genera previously included in Dacampiaceae indicates that the family is strongly polyphyletic and that the type species of Dacampia is placed in Pleosporales. The genus Munkovalsaria s. str. is placed in Didymosphaeriaceae (Pleosporales). Polycoccum s. str. and two species of Clypeococcum are shown to form a new lineage sister to the Trypetheliaceae in Trypetheliales and described here as Polycoccaceae. Other members of Polycoccum s. lat. are included in the Pleosporales and are closely related to lichenicolous Phoma-like species of the family Phaeosphaeriaceae. The genus Didymocyrtis is resurrected for these species and for lichenicolous species previously assigned to Diederichia, Diederichomyces, Leptosphaeria and Phoma. The genera Diederichia and Diederichomyces are synonymized with Didymocyrtis. The new combinations Didymocyrtis bryonthae, D. cladoniicola, D. foliaceiphila, D. infestans, D. kaernefeltii, D. melanelixiae, D. pseudeverniae, D. ramalinae, D. slaptoniensis and D. xanthomendozae are made, and the new name D. epiphyscia is introduced for Phoma physciicola. Some anamorph-teleomorph relationships are resolved, such as Didymocyrtis ramalinae–Phoma ficuzzae and Didymocyrtis consimilis–Phoma caloplacae, the phylogenetic results being supported by single ascospore cultures that lead to the asexual stage producing pycnidia and conidia in culture. Speciation by host switching is assumed to be important in the genus Didymocyrtis. An identification key to Didymocyrtis species is provided.