Neohelicomyces wuzhishanensis X. Y. Ma, Y. Z. Lu & J. Ma 2025, sp. nov.

Neohelicomyces wuzhishanensis X. Y. Ma, Y. Z. Lu & J. Ma sp. nov. Fig. 3 Etymology. “ wuzhishanensis ” refers to the type location “ Wuzhishan National Nature Reserve. ” Holotype. HKAS 128942 Description. Saprobic on submerged decaying wood in a freshwater habitat. Sexual morph Undetermined. Asexual morph Hyphomycetous, helicosporous. Colonies on natural substrate superficial, effuse, gregarious, white. Mycelium partly immersed, composed of hyaline to pale brown, branched, septate, guttulate, smooth hyphae. Conidiophores 92–190 × 3.5–5 μm (x – ̄ = 140 × 4.5 μm, n = 25), macronematous, mononematous, erect, cylindrical, widest at the base, tapering towards narrow apex, straight or slightly flexuous, occasionally branched, septate, subhyaline to pale brown, thick-walled. Conidiogenous cells 9.5–16.5 × 2.5–5 μm (x – ̄ = 14 × 4 μm, n = 20), holoblastic, monoblastic, or polyblastic, integrated, intercalary or terminal, cylindrical, with tiny tooth-like or bladder-like protrusions, subhyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, tapering towards the rounded ends, developing on tooth-like protrusions, 23–26 μm diam., and conidial filament 2.3–3.5 μm wide (x – ̄ = 24.5 × 2.8 μm, n = 20), 118–143.5 μm long (x – ̄ = 129 μm, n = 20), tightly coiled 1.5–2 times, becoming loosely coiled in water, aseptate, guttulate, hyaline, smooth-walled. Culture characteristics. Conidia germinate on PDA within 14 hours, producing germ tubes from the conidial body. Colonies on PDA are irregular with a raised surface and undulate margin, reaching 3 cm in diameter after 39 days at room temperature (approximately 25 ° C), and are brown to dark brown on both the surface and reverse sides. Material examined. China • Hainan Province, Wuzhishan City, Shuimanhe tropical rainforest scenic area in Wuzhishan, 18°92'N, 109°63'E, on rotting wood in a freshwater habitat, 15 August 2021, Jian Ma, WZS 8.2 (HKAS 128942, holotype), ex-type living cultures GZCC 23-0410; • Ibid., WZS 8.5 (GZAAS 24-0078, paratype), living culture GZCC 24-0164. Notes. In our phylogenetic tree (Fig. 1), our isolates (GZCC 23-0410 and GZCC 24-0164) formed a sister clade to N. guizhouensis (GZCC 23-0725) with 92 % ML bootstrap support. Neohelicomyces wuzhishanensis (HKAS 128942) can be distinguished from N. guizhouensis (KAS 134924) by its wider conidial diameters (23–26 μm vs. 18–21.5 μm) (Ma et al. 2024 a). Moreover, base pair comparison of N. wuzhishanensis (GZCC 23-0410) and N. guizhouensis (GZCC 23-0725) shows 31 / 539 bp differences in ITS (5.8 %, gaps 13 bp), 4 / 530 bp differences in LSU (0.8 %, gaps 3 bp), 13 / 877 bp differences in tef 1 - α (1.5 %), and 23 / 939 bp differences in rpb 2 (2.4 %). Therefore, based on the multigene phylogenetic analysis and morphological differences, we introduce N. wuzhishanensis as a novel species.