Neohelicomyces astrictus C. G. Lin, K. D. Hyde & Jian K. Liu, Fungal Diversity [225] (2025)
Fig. 2
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, branched, septate, smooth, hyaline to pale brown, with masses of crowded, glistening conidia. Conidiophores 50–350 × 4–9 µm (x ̄ = 200 × 6 μm, n = 20), macronematous, mononematous, cylindrical, unbranched, septate, thick-walled, hyaline to pale brown. Conidiogenous cells 10–17 × 3.5–9 µm (x ̄ = 15 × 5 μm, n = 30), holoblastic, polyblastic, integrated, terminal and intercalary, cylindrical, smooth-walled, hyaline to pale brown, with denticles; denticles 1.4–4.4 × 0.9–2.6 µm (x ̄ = 3.4 × 1.4 μm, n = 30), hyaline. Conidia 90–170 × 2–3.3 µm (x ̄ = 121 × 2.6 μm, n = 30), helicoid, solitary, acropleurogenous, rounded at tip, 15–18 μm diam, tightly coiled 2–3 times, becoming loosely coiled in water, indistinctly multi-septate, guttulate, smooth-walled, hyaline.
Cultural characteristics.
Conidia germinated on PDA medium within 12 h and germ tube produced from conidia. Colonies on PDA medium reaching to 40 mm diam. after 43 days at 25 ° C under natural light, dry, dense, with irregular shape, raised surface, undulated margin, brown to dark brown. The reverse is pale brown to dark brown, becoming paler near the center.
Material examined.
China • Guizhou Province, Qiandongnan Miao and Dong Autonomous Prefectur, Zhenyuan County, 27°14'40"N, 108°18'30"E, altitude 625 m, on submerged decaying wood in a stream, 3 May 2025, Xingjuan Xiao, GS 33 (GZAAS 25-07820), living culture GZCC 25-27619; ibid. GS 33 b (GZAAS 25-07821), living culture GZCC 25-27620.
Notes.
Phylogenetic results showed that the new isolates GZCC 25-27619 and GZCC 25-27620 clustered with Neohelicomyces astrictus (HKAS 105122, ex-type), with support values of 97 % ML / 1.00 BYPP (Fig. 1). Pairwise nucleotide comparisons revealed that the new isolate GZCC 25-27619 is similar to HKAS 105122 in 479 / 486 bp (99 %) of the ITS region, 764 / 764 bp (100 %) of the LSU region, and 883 / 883 bp (100 %) of the LSU 1 - αα region. Morphologically, our isolate is consistent with the holotype HKAS 10-5122 of Neohelicomyces astrictus in key diagnostic features, including helicoid, hyaline conidia and similar conidiogenous cell (Lin et al. 2025). However, it differs in having longer conidiophores (50–350 μm vs. 22–161 μm) and somewhat longer conidia (90–170 μm vs. 100–136.5 μm). Despite these minor differences, the overall morphology and phylogenetic placement support its identification as N. astrictus. Notably, our specimen was collected from a freshwater habitat, whereas HKAS 10-5122 was reported from a terrestrial habitat (Lin et al. 2025), representing a new habitat record for this species.
Publication Date: 2026-06-17