Cryptococcomyces Lan Zhuo & C. L. Hou, 2025

Zhuo, Lan, Wang, Hai-Qi, Zhang, Peng, Sui, Xiao-Nan, Guo, Mei-Jun, Wang, Shi-Juan & Hou, Cheng-Lin, 2025, New genera and species of coniferous twig-inhabiting Rhytismatales from China, IMA Fungus 16, pp. e 138790-e 138790 : e138790-

Cryptococcomyces Lan Zhuo & C. L. Hou gen. nov.

Etymology.

Crypto (Latin) = hidden, referring to the hidden ascomata of the type and morphological similarity with species of the genus Coccomyces .

Diagnosis.

Species of this new genus are morphologically similar to some species of Coccomyces that inhabit coniferous twigs and bark, but are phylogenetically distant from the type of Coccomyces , Co. tumidus , which inhabits leaves, as shown in the phylogenetic tree.

Type.

Cryptococcomyces occultus Lan Zhuo & C. L. Hou , described below.

Sexual morph.

Ascomata on twigs of Juniperus spp. , scattered, round, elliptical or slightly irregular, black (# 000000) or concolorous with the surface of the substrate, opening by radial or irregular splits to expose a pale yellow (# ffff 9 d) to pale orange (# ffa 500) hymenium. Lips absent. Ascomata intracortical. Covering stroma well developed. Basal Covering stroma absent or present, consisting of carbonized, thick-walled, angular to globose cells. Internal matrix of Covering stroma absent or present, consisting of hyaline, thin-walled, angular cells and short hyphae; in some species, the matrix is filled with crystals. Subhymenium flat or slightly depressed, consisting of hyaline textura porrecta. Paraphyses filiform, branched or not branched, not swollen at tips. Asci ripening sequentially, clavate, thin-walled, J –, 8 - spored. Ascospores aseptate, filiform, hyaline, covered or not covered by a gelatinous sheath.

Asexual morph.

Conidiomata and zone lines not seen.

Notes.

Phylogenetically, molecular sequence data obtained from specimens cited below for species of Cryptococcomyces cluster together with a sequence in GenBank labelled “ Colpoma juniperi (P. Karst.) Dennis Lantz 395 ” with high support (MLB = 99 %, PP = 0.97; Clade 1, Fig. 1 ). According to molecular sequence data, this clade is distantly related to the type species of Colpoma , Colpoma quercinum (Pers.) Wallr. Species of Cryptococcomyces do not belong to the genus Colpoma according to molecular sequence data.

In addition, the round ascomata with radial or irregular openings of the species in the new genus resemble those of the genus Coccomyces rather than Colpoma ( Sherwood 1980; Johnston 1991). However, the clade formed by molecular sequences of Cryptococcomyces is phylogenetically distinct from the type of Coccomyces , Co. tumidus . Therefore, these species are not congeneric with Coccomyces . Additionally, species in Cryptococcomyces all grow on twigs of Juniperus spp. Based on morphological characteristics, phylogenetic analysis, and the host relationship, Cry. juniperi is proposed to belong to the genus Cryptococcomyces .

Figures

Figure 1. Phylogenetic tree derived from maximum likelihood analysis of combined ITS, nrLSU, and mtSSU rDNA sequences of Rhytismatales, using Cudoniella clavus (AFTOL-ID 166) and Pezicula carpinea (KUS-F 51029) as outgroups. Bootstrap support values for ML analysis (MLB) and MP analysis (MPB) greater than 70 % and Bayesian posterior probabilities (PP) greater than 0.95 are given above the nodes. Names of new species and a new combination are written in bold. Species name T – Type species; Species name H – Holotype.