Two novel lignicolous freshwater fungi, Conioscypha xizangensis and Cordana linzhiensis, from the Tibetan Plateau, China

Lignicolous freshwater fungi form a highly diverse group and are primarily distributed in the classes Dothideomycetes and Sordariomycetes. During an investigation of lignicolous freshwater fungi on the Tibetan Plateau, China, four collections were obtained from submerged wood in freshwater habitats. Morphological studies combined with multi-gene phylogenetic analysis based on ITS, LSU, SSU, and RPB2 indicated that the collected taxa belonged in the orders Conioscyphales and Cordanales in Sordariomycetes. Based on evidence from morpho-molecular analyses, two new species, Conioscypha xizangensis and Cordana linzhiensis, are introduced with descriptions of their hyphomycetous asexual states. Conioscypha xizangensis shows a close phylogenetic relationship with Conioscypha tenebrosa but, unlike that species, has phialidic and integrated conidiogenous cells. Cordana linzhiensis forms a distinct clade within the genus and possesses unique characteristics compared with existing species in having swollen conidiophores, polyblastic, clavate, or cylindrical conidiogenous cells, and solitary or acropleurogenous conidia with a hyaline mucoid sheath. These new discoveries further add to the diversity of freshwater fungi on the Tibetan Plateau.