Synnematotriadelphia gen. nov. (S. stilboidea comb. nov. and S. synnematofera comb. nov.) and Triadelphia hexaformispora sp. nov. in the family Triadelphiaceae

During our studies of microfungi from Thailand, Triadelphia hexaformispora sp. nov. collected from decaying wood in a freshwater habitat in Nan Province, Thailand, is described and illustrated. Based on newly generated sequences of the nuclear ribosomal DNA and partial sequence of the second largest subunit of RNA polymerase, Triadelphia species clustered in two monophyletic sister clades in Triadelphiaceae (Microascales, Hypocreomycetidae, Sordariomycetes), one clade accommodates T. heterospora, the type species of Triadelphia, T. diversa, T. loudetiae, T. hexaformisspora, and T. romanica and the second clade incudes T. moubasheri, T. pulvinata, and T. disseminata. Two other species, Triadelphia stilboidea and T. synnematofera (morphological data only) group in a separate clade for which we propose the new genus Synnematotriadelphia. Molecular clock analyses suggest that Triadelphiaceae evolved in the middle Cretaceous, ca. 105 (74-142) million years ago.