The Morphological Characteristics and Phylogenetic Analyses Revealed an Additional Taxon in Heteroradulum (Auriculariales)

Auriculariales is diverse, embracing a number of corticioid, poroid, and hydnoid genera. The present study covers a new wood-inhabiting fungal species of Heteroradulum niveum sp. nov that is proposed on the basis of a combination of morphological features and molecular evidence. The species is characterized by the resupinate basidiomata, a monomitic hyphal system with generative hyphae with clamp connections; tubular cystidia; two- to four-celled basidia; and allantoid, colorless, thin-walled, smooth, IKI-, CB-, basidiospores (6.5-13.5 x 2.7-5.5 mu m). Sequences of ITS and nLSU rRNA gene regions of the specimens were generated, and phylogenetic analyses were carried out with methods of maximum parsimony, maximum likelihood, and Bayesian inference. These phylogenetic analyses inferred from ITS+nLSU indicated that H. niveum is nested in Heteroradulum within Auriculariales. Further study within Heteroradulum on the basis of ITS+nLSU dataset revealed that it formed a monophyletic lineage with a strong support (100% BS, 100% BP, 1.00 BPP) and then grouped with H. yunnanensis.

Automated summary

A new species of wood-inhabiting fungal species, Heteroradulum niveum sp. nov, is reported and described in this study based on morphological and molecular evidence. Phylogenetic analysis using ITS and nLSU gene sequences suggests that H. niveum belongs to the genus Heteroradulum within the order Auriculariales.