Revision of Cerinomyces (Dacrymycetes, Basidiomycota) with notes on morphologically and historically related taxa

Cerinomyces (Dacrymycetes, Basidiomycota) is a genus traditionally defined by corticioid basidiocarps, in contrast to the rest of the class, which is characterized by gelatinous ones. In the traditional circumscription the genus is polyphyletic, and the monotypic family Cerinomycetaceae is paraphyletic. Aiming for a more concise delimitation, we revise Cerinomyces s.l. with a novel phylogeny based on sequences of nrDNA (SSU, ITS, LSU) and protein-coding genes (RPB1, RPB2, TEF1-α). We establish that monophyletic Cerinomyces s.s. is best characterized not by the corticioid morphology, but by a combination of traits: hyphal clamps, predominantly aseptate thin-walled basidiospores, and low content of carotenoid pigments. In our updated definition, Cerinomyces s.s. encompasses five well-supported phylogenetic clades divided into two morphological groups: (i-iii) taxa with arid corticioid basidiocarps, including the generic type C. pallidus; and (iv-v) newly introduced members with gelatinous basidiocarps, like Dacrymyces enatus and D. tortus. The remaining corticioid species of Cerinomyces s.l. are morphologically distinct and belong to the Dacrymycetaceae: our analysis places the carotenoid-rich Cerinomyces canadensis close to Femsjonia, and we transfer the clamps-lacking C. grandinioides group to Dacrymyces. In addition, we address genera related to Cerinomyces s.l. historically and morphologically, such as Ceracea, Dacryonaema and Unilacryma. Overall, we describe twenty-four new species and propose nine new combinations in both Cerinomycetaceae and Dacrymycetaceae.