China and Thailand are rich in fungal diversity with abundant freshwater resources that are favorable for numerous fungal encounters. Resulting from this, the majority of the Dictyosporiaceae species reported were from these two countries. During the investigation on the diversity of lignicolous freshwater fungi in the Greater Mekong Subregion, eleven collections of cheirosporous species on submerged wood were collected from lentic and lotic habitats in China and Thailand. Phylogenetic analysis that combined nuclear small-subunit ribosomal RNA (SSU), internal transcribed spacer region (ITS), nuclear large subunit ribosomal RNA (LSU) and translation elongation factor 1α (tef 1-α) loci revealed six new species: Dictyocheirospora chiangmaiensis, D. multiappendiculata, D. suae, Digitodesmium aquaticum, Vikalpa grandispora and V. sphaerica. In addition, four known species were also identified and reported based on morphological and phylogenetic evidence. The detailed descriptions and illustrations of these taxa are provided with an updated phylogenetic tree of Dictyosporiaceae.
Keywords: asexual morph; lignicolous freshwater fungi; new species; phylogeny; taxonomy.