Neocotylidia gen. nov. (Hymenochaetales, Basidiomycota) Segregated from Cotylidia Based on Morphological, Phylogenetic, and Ecological Evidence

Taxonomic and phylogenetic studies of <i>Cotylidia</i> (Hymenochaetales, Basidiomycota) were performed. A phylogenetic estimate based on six genetic markers revealed that <i>Cotylidia</i> in the current sense includes species belonging to three distantly related clades in the Hymenochaetales. Based on morphology, phylogeny, and ecological habitat, the name <i>Cotylidia</i> s.s. is proposed for the first clade, including the type species <i>C. undulata</i> and <i>C. carpatica</i>. <i>Neocotylidia</i> gen. nov. is proposed for the second clade, which includes <i>N. diaphana</i>, <i>N. fibrae</i>, the new species <i>N. bambusicola</i>, and two accessions recorded as <i>Cotylidia aurantiaca</i> var. <i>alba</i> and <i>C. aurantiaca</i>. Contrary to the findings in earlier studies, <i>C. pannosa</i> demonstrated a weak grouping affinity with <i>Globulicium hiemale</i>, <i>Hastodontia hastata</i>, <i>Atheloderma mirabile</i>, <i>Tsugacorticium kenaicum</i>, <i>Lawrynomyces capitatus</i>, and <i>Lyoathelia laxa</i>. The morphological characteristics of <i>Cotylidia</i> s.s. are restricted to species with hymenial cystidia, pileocystidia, and caulocystidia, as well as a muscicolous habitat. <i>Neocotylidia</i> species differ from <i>Cotylidia</i> s.s. in the lack of pileocystidia and caulocystidia and substrate preference for soil or wood. Illustrated descriptions of the new species and genus, as well as an identification key to the worldwide species of <i>Cotylidia</i> s.l. are provided.