Morphological and molecular identification of two new wood-inhabiting species (Russulales, Basidiomycota) from China

Wood-inhabiting fungi represent a highly diverse group of microorganisms that play essential roles in forest ecosystems. However, the species diversity of wood-inhabiting fungal taxa in the order Russulales has not been systematically documented in the high-altitude forests of Yunnan Province, China. In the present study, the detailed morphological characteristics and combined multi-locus phylogeny of the internal transcribed spacers (ITS) and the large subunit (nrLSU) of the nuclear ribosomal DNA (rDNA) revealed two new species in Russulales, viz., Gloeopeniophorella luteola and Scytinostroma tenuissimum.

Gloeopeniophorella luteola is characterized by its membranaceous, thin basidiomata with a smooth hymenial surface, a monomitic hyphal system with simple septa, generative hyphae, and gloeocystidia, and thick-walled basidiospores measuring 4–4.9 × 3.8–4.4 µm. Scytinostroma tenuissimum is characterized by its soft membranaceous basidiomata with a cream to pale pink hymenial surface, a dimitic hyphal system with clamped generative hyphae, and ellipsoid basidiospores measuring 10.1–13.2 × 7.1–9.3 µm.

Phylogenetic analysis based on the concatenated ITS + nLSU dataset demonstrated that the two new species grouped within the order Russulales, in which G. luteola grouped into the family Russulaceae, while S. tenuissimum grouped into the family Peniophoraceae, and G. luteola was sister to G. bambusicola, and S. tenuissimum grouped together with S. acystidiatum and S. bambusinum. Comprehensive descriptions, micrographs, and phylogenetic analyses of the two new species are provided.