Stipamyces 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-

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

Etymology.

Stipa - from stipes (Latin) = stalk, referring to the stalked ascomata.

Diagnosis.

This new genus is similar to Tryblidiopsis , but differs in having aseptate ascospores.

Type.

Stipamyces pinicola (R. H. Lei & C. L. Hou) Lan Zhuo & C. L. Hou

Sexual morph.

Ascomata on twigs of Pinus spp. , erumpent, stalked, scattered or aggregate, round or slightly irregular, black, opening by irregular splits. In median vertical section, covering stroma well developed. Basal Covering stroma absent. Internal matrix of Covering stroma present, consisting of hyaline, thin-walled, interwoven hyphae. Subhymenium consisting of small, hyaline cells. Paraphyses filiform, circinate at tips. Asci clavate, thin-walled, J –, 8 - spored. Ascospores aseptate, long-fusiform, hyaline, not covered by a thick gelatinous sheath.

Asexual morph.

Conidiomata and zone lines not seen.

Notes.

Based on the phylogenetic analysis, the molecular sequences of Stipamyces spp. form a well-supported clade (MLB = 100 %, MPB = 82 %, PP = 1.00; Clade 7, Fig. 1 ), and appear to be closely related to Pseudococcomyces yunnanensis . Pseudococcomyces yunnanensis differs from Stipamyces spp. by sessile ascomata. Species within the genus Tryblidiopsis also possess stalked ascomata, but the ascospores of Tryblidiopsis spp. are typically septate. Furthermore, in the phylogenetic tree, the sequences of species of these two genera are distant. Thus, Stipamyces is treated as a new genus.

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.