Xylodon asiaticus (Hymenochaetales, Basidiomycota), a new species of corticioid fungus from southern China

The corticioid fungi are a cosmopolitan group and show a rich diversity, growing in the vegetation of boreal, temperate, subtropical, and tropical regions. Xylodon daii sp. nov. was found in the Yunnan Province, China, which suggested here to be new fungal species in light of their morphology and phylogeny. Xylodon daii has a coriaceous basidiomata with a hydnoid hymenophore and a monomitic hyphal system having generative hyphae with clamp connections, and ellipsoid to subcylindrical basidiospores measuring as 4–5.2 × 2.8–3.5 µm. Sequences of the ITS and nLSU rRNA markers of the studied samples were generated, and phylogenetic analyses were performed using the maximum likelihood, maximum parsimony, and Bayesian inference methods. After a series of phylogenetic studies, the ITS+nLSU analysis of the order Hymenochaetales indicated that, at the generic level, six genera, (i.e., Fasciodontia, Hastodontia, Hyphodontia, Lyomyces, Kneiffiella and Xylodon) were accommodated the members of Hyphodontia sensu lato, and the genus Xylodon grouped with Lyomyces within the Hymenochaetales. According to a further analysis of the ITS dataset, X. daii was nested into the genus Xylodon, in which it was retrieved as a sister to X. pseudotropicus.