Neohelicomyces coffeae M. Y. Han & S. Tibpromma 2026, sp. nov.

Neohelicomyces coffeae M. Y. Han & S. Tibpromma sp. nov. Fig. 2 Etymology. The species epithet “coffeae” refers to the host genus Coffea. Holotype. GMB -W 1490. Description. Saprobic on dead branches of C. arabica. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on natural substrate superficial, effuse, gregarious, white, can be seen as a white bush with the naked eye. Mycelium partly immersed to superficial, composed of hyaline to pale brown, branched, septate, smooth hyphae. Colonies composed of numerous coiled, spirally twisted, hyaline conidia aggregated in fascicles, which reflect light and impart a glistening, sparkling appearance to the colony surface. Conidiophores 144.5–274 × 3.4–6.2 μm (x ̄ = 201 × 4.6 μm, n = 30), macronematous, mononematous, erect or sub-erect, produced singly or in groups, some arising from creeping hyphae, cylindrical, straight or slightly flexuous, occasionally branched, septate, subhyaline to pale brown, thick-walled. Conidiogenous cells 13.2–20.6 × 3.4–5.2 μm (x ̄ = 17 × 4.1 μm, n = 25), holoblastic, monoblastic or polyblastic, integrated, terminal or intercalary, cylindrical, with denticles, hyaline, smooth-walled, truncate at apex after conidial secession, subhyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, tapering towards the rounded ends, developing on a tooth-like protrusion, 13.5–19.4 μm diam. (x ̄ = 17.1 μm, n = 25) and conidial filament 2.1–3.3 μm wide (x ̄ = 2.8 μm, n = 25), 105.3–146.4 μm long (x ̄ = 132 μm, n = 25), tightly coiled 2.5–3.75 times, loosely coiled three times, becoming loosely coiled in water, multi-septate, hyaline to subhyaline, some in pale brown, smooth-walled, granules. Culture characteristics. Conidia germinated on PDA and produced germ tubes within 12 h. Colonies on PDA reaching 22 mm diam. after two weeks of incubation at 28 ° C with an irregular shape, rough surface, slightly raised, radially striated with a lobate edge. Colony surface centrally dark brown to chestnut-brown, becoming paler towards the periphery; aerial mycelium sparse to moderate, whitish at the margin. Reverse side uniformly dark brown. Material examined. China • Yunnan Province, Pu’er City, Simao District (22°36'36"N, 101°0'14"E, 1189 m), on dead branches of C. arabica L., 1 August 2024, M. Y. Han, (BG 55 = GMB -W 1490, holotype), ex-type GMBCC 2225, other living culture GMBCC 2226. GenBank number. GMBCC 2225 = ITS: PX 308843, LSU: PX 308848, tef 1 - α: PX 314510, rpb 2: PX 314514 and GMBCC 2226 = ITS: PX 308844, LSU: PX 308849, tef 1 - α: PX 314511, rpb 2: PX 314515. Notes. In the phylogenetic analyses (Fig. 1), our collections of N. coffeae [GMBCC 2225 (ex-type) and GMBCC 2226] clustered with N. edgeworthiae (CGMCC 3.25565) as a sister lineage, receiving 100 % ML / 1.00 PP support. Comparisons of nucleotide sequences between N. coffeae and N. edgeworthiae revealed minor overall differences; however, the ITS region showed a 14 / 550 bp (2.54 %, 5 gaps) difference. Morphologically, the conidiogenous cells of our isolates are notably longer than those of N. edgeworthiae (13.2–20.6 μm vs. 9–14 μm) (Ma et al. 2024 b). Conversely, the conidia of our collections are significantly smaller than those of N. edgeworthus, both in diameter (13.5–19.4 μm vs. 21.5–34 μm) and length (105.3–146.4 μm vs. 121–177 μm) (Ma et al. 2024 b). In addition, the conidia of N. edgeworthiae are aseptate and have numerous guttulate, whereas conidia of our collections are multi-septate, lack guttulate, and have only surface granules (Ma et al. 2024 b). In summary, although the nucleotide divergence between our collections and N. edgeworthiae is relatively low, the combination of distinct morphological characters and phylogenetic position supports their separation, and therefore, we introduce N. coffeae herein as a novel species.