Neohelicomyces wujiangensis L. J. Zhang, Y. Z. Lu & X. J. Xiao sp. nov.
Fig. 4
Etymology.
Referring to the type locality (Wujiang River), where the holotype was collected.
Holotype.
GZAAS 25-07824.
Description.
Saprobic on decaying wood in a freshwater habitat. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on natural substrate superficial, white, gregarious, glistening. Mycelium partly superficial, partly immersed, composed of branched, septate, smooth, pale brown to brown hyphae. Conidiophores 35–120 × 3–6.5 µm (x ̄ = 70 × 4 μm, n = 20), macronematous, mononematous, erect, mostly simple, flexuous, cylindrical, hyaline to pale brown, septate, thick-walled. Conidiogenous cells holoblastic, monoblastic or polyblastic, integrated or discrete, sympodial, terminal or intercalary, cylindrical or repeatedly geniculate, smooth-walled, hyaline to brown, truncate at apex after conidial secession. Conidia 150–300 × 2–4 µm (x ̄ = 230 × 3 μm, n = 30), helicoid, solitary, acropleurogenous, rounded at tip, 21–32 μm diam, tightly coiled 3 2 / 3 –4 times, becoming loosely coiled in water, indistinctly multiseptate, guttulate, smooth-walled, hyaline.
Cultural characteristics.
Conidia germinated on PDA within 12 h, and germ tube produced from conidial filaments. Colonies on PDA medium reaching to 25 mm diam. after 33 days at 28 ° C under natural light, dry, dense, with irregular shape, raised surface, and filamentous margin, pale brown. The reverse is pale brown to dark brown, becoming paler near the center. No diffusible pigment was observed.
Material examined.
China • Guizhou Province, Bijie City, Wujiang river, 26°48'19"N, 106°6'9"E, altitude 940 m, on submerged decaying wood in Wujiang river, 21 July 2025, Xingjuan Xiao, HLS 33 (GZAAS 25-07824, holotype), ex-type culture GZCC 25-27623; ibid. HLS 33 b (GZAAS 25-07825, isotype), ex-isotype culture, GZCC 25-27624.
Notes.
In the phylogenetic tree (Fig. 1), our two new strains GZCC 25-27623 and GZCC 25-27624 formed a distinct clade and were sister to Neohelicomyces davidii (GZCC 24-0290, ex-type), with support values of 100 % ML / 1.00 BYPP. Pairwise nucleotide comparisons showed that N. wujiangensis (GZCC 25-27623, ex-type) and N. davidii (GZCC 24-02907, ex-type) share 402 / 424 bp (95 %) similarity in the ITS region, 778 / 779 bp (99 %) in the LSU region, 1048 / 1066 bp (98 %) in the rpb 2 region, and 857 / 874 bp (98 %) in the LSU 1 - α region, excluding gaps. Morphologically, the new isolate differs from N. davidii (HKAS 145875, holotype) by having shorter conidiophores (35–120 µm vs. 52–169 µm) and white colonies on the natural substrate, whereas those of N. davidii are white to pale pink (Xiao et al. 2025). In culture, N. davidii forms colonies with a rough surface and undulate margins, whereas N. brevis produces dense, dry colonies with a raised surface and filamentous margins (Xiao et al. 2025). Based on both molecular and morphological evidence, the new species Neohelicomyces wujiangensis is herein proposed.
Publication Date: 2026-06-17