Hyalosympodium gen. et sp. nov. (Pararamichloridiales, Diaporthomycetidae) from freshwater habitats in Guizhou, China

A novel genus, Hyalosympodium, is proposed to accommodate a lignicolous freshwater hyphomycete isolated from decaying wood collected in Guizhou Province, China. The taxon is established based on an integrative approach combining detailed morphological observations and multilocus phylogenetic analyses of LSU, ITS, SSU, and rpb 2 sequence data. Phylogenetically, Hyalosympodium aquaticum represents a monophyletic lineage within Pararamichloridiales and is resolved as sister to Tenebrosynnematica obclavata, with strong statistical support.

Morphologically, Hyalosympodium is characterized by macronematous, synnematous, grouped, cylindrical, septate, subhyaline to brown conidiophores; polyblastic, integrated, sympodial, cylindrical, smooth, subhyaline to pale brown conidiogenous cells; and acropleurogenous, ellipsoidal to oval, guttulate, hyaline conidia. A comprehensive taxonomic treatment is provided, including detailed morphological descriptions, illustrations, and a phylogenetic tree to support the establishment of the new genus and species.