Neohelicosporium submersum H. Zhang, W. Dong & K.D. Hyde
Index Fungorum number: IF557943; Facesoffungi number: FoF09288
Etymology: in reference to the submerged habitats of the fungus
Holotype: MFLU 17-1734
Saprobic on decaying, submerged wood in freshwater. Sexual morph: Undetermined. Asexual morph: Colonies superficial, effuse, gregarious, white. Mycelium composed of partly immersed, partly superficial, hyaline to pale brown, septate hyphae, with mass of crowded conidia. Conidiophores long or short, uneven in width, 50–260 × 4–5.5 µm (x̄ = 147 × 4.9 µm, n = 10), macronematous, mononematous, unbranched, erect, cylindrical, tapering at tip, pale brown, septate, slightly constricted at septa, smooth-walled, thin-walled. Conidiogenous cells 13–17 × 4–5.5 µm (x̄ = 15 × 4.8 µm, n = 5), holoblastic, mono- to polyblastic, integrated, determinate or sympodial, mostly intercalary or rarely terminal, cylindrical, with tiny tooth-like protrusions, mostly bearing one, rarely two tiny conidiogenous loci, 4 × 1.5 µm, pale brown, smooth-walled, loosely arranged. Conidia solitary, dry, mostly pleurogenous or rarely acrogenous, helicoid, rounded at tip, 47–52 µm diam. when tightly coiled, 55–70 µm diam. when loosely coiled, and conidial filament 3–5 µm wide (x̄ = 50 × 4 µm, n = 5), 340–400 µm long, tightly coiled 3–3.25 times, multi-septate, guttulate, hyaline, smooth-walled. (Description from Dong et al. 2020)
Culture characteristics: On PDA, colony circular, reaching 60 mm in 60 days at 25 °C, black from above and below, surface rough, with sparse mycelium, dry, edge entire. Mycelium mostly immersed, dark brown, septate, smooth.
Material examined: THAILAND, Phang Nga Province, on submerged wood in a stream, 1 September 2017, X.D. Yu, v7 (MFLU 17-1734, holotype), ex-type living culture MFLUCC 17-2376.
Notes: Neohelicosporium submersum clusters with two unnamed Neohelicosporium spp. (HKUCC 10235 and CBS 189.95). Our isolate MFLUCC 17-2376 is identical to HKUCC 10235 and CBS 189.95 based on available sequences (LSU of HKUCC 10235 and ITS, LSU, SSU of CBS 189.95). We introduce N. submersum, but do not include these two strains because their morphological data and some molecular data are lacking. Neohelicosporium submersum differs from another phylogenetically related species N. krabiense by longer conidiophores (50–260 × 4–5.5 µm vs. 45–140 × 5–6.5 µm) and larger conidia (47–52 µm diam., 340–400 µm long vs. 30–40 µm diam., 230–320 µm long). (Notes from Dong et al. 2020)
Freshwater distribution: Thailand (Dong et al. 2020)