Comoclathris desertica X. G. Tian, T. Y. Du & D. F. Bao 2026, sp. nov.

Comoclathris desertica X. G. Tian, T. Y. Du & D. F. Bao sp. nov. Fig. 3 Etymology. Named after the desert habitat from where the holotype was collected. Holotype. GMB-W 1518. Description. Saprobic on dead branches of an unidentified wood. Sexual morph: Ascomata 90–200 × 70–190 μm (x ̄ = 115 × 116 μm, n = 5), solitary, scattered or aggregated, immersed, not obvious on the surface of the host, subglobose, black, ostiole not obvious. Peridium 10–30 μm wide, comprising thin-walled cells of textura angularis, dark brown to black. Hamathecium comprising numerous, 2 μm wide, filamentous, septate, branched, cellular pseudoparaphyses, hyaline, embedded in a gelatinous matrix, extending above the asci. Asci 65–85 × 18–23 μm (x ̄ = 76 × 20 μm, n = 30), bitunicate, fissitunicate, 8 - spored, cylindrical-clavate, short pedicellate, apically rounded. Ascospores 16–23 × 8–10 μm (x ̄ = 19 × 9 μm, n = 30), 1 - seriate, slightly overlapping, fusiform, initially yellowish, becoming brown to dark brown, muriform, with 3 transversely septa and 1 vertical septum, consisting of 6 cells, upper end conical, lower end tapered gradually, apical cell mostly undivided, straight or slightly curved, smooth-walled, surrounded by a mucilaginous sheath. Asexual morph: Undetermined. Culture characteristics. Ascospores germinated on PDA within 12 h at 28 ° C, and germ tubes were produced around spores. Colonies on PDA reached 2 cm diam. after one week at 28 ° C. Colonies obverse: circular, white-cream to grey, with sparsely hairy edge; grey from below, the active hyphae at the edge are white. Material examined. China • Inner Mongolia Autonomous Region, Ordos City, Xiangshawan, on dead branches of an unidentified wood in the desert, 01 October 2023, J. Y. Zhang, BTD 24 (GMB-W 1518, holotype), ex-type, GMBCC 2307, other living culture, GMBCC 2320. GenBank numbers. GMBCC 2307: ITS = PX 660512, LSU = PX 660516, SSU = PX 660508, rpb 2 = PX 672979; GMBCC 2320: ITS = PX 660513, LSU = PX 660517, SSU = PX 660509, rpb 2 = PX 672980. Notes. Comoclathris desertica clustered with C. clematidis (CCMJ 13076, ex-type and CCMJ 13077) and C. xanthoceratis (CCMJ 13078, ex-type and CCMJ 13079) in the phylogenetic tree with 100 % in ML and 1.00 in BYPP statistical support (Fig. 2). A nucleotide base pair differences between our new strain (GMBCC 2307, ex-type) and C. clematidis (CCMJ 13076, ex-type) in ITS, LSU, SSU, and rpb 2 (without gaps) showed a 2.70 % (14 / 519 bp) difference in ITS, 1.33 % (9 / 679 bp) difference in LSU, 0.32 % (2 / 628 bp) difference in SSU, and 5.58 % (47 / 842 bp) difference in rpb 2. Between our new strain (GMBCC 2307, ex-type) and C. xanthoceratis (CCMJ 13078, ex-type), there was a 2.35 % (12 / 510 bp) difference in ITS, 1.18 % (8 / 676 bp) difference in LSU, 0.32 % (2 / 628 bp) difference in SSU, and 6 % (52 / 866 bp) difference in rpb 2. Morphologically, C. desertica is similar to C. clematidis and C. xanthoceratis, both of which have ascospores with 3 transverse septa and a vertical septum, surrounded by a thick mucilaginous sheath. But C. desertica is different from C. clematidis and C. xanthoceratis in having immersed ascomata, and dark brown ascospores, 1 - seriate, slightly overlapping, smooth-walled; while C. clematidis has immersed to erumpent ascomata, and brown ascospores, with verrucose or echinulate wall (Xu et al. 2024); while C. xanthoceratis has immersed to semi-immersed ascomata, and brown to dark brown ascospores, 1–2 - seriate (Xu et al. 2024). And our collection displays comparatively smaller ascospores than these two species (viz., C. desertica: 19 × 9 μm, C. clematidis: 30 × 14 μm, C. xanthoceratis: 37 × 16 μm). Therefore, C. desertica is introduced as a new species from China based on morphological and molecular evidence as recommended by Jeewon and Hyde (2016).