Neohelicosporium krabiense Y.Z. Lu, J.C. Kang & K.D. Hyde
Index Fungorum number: IF 554872; Facesoffungi number: FoF 04740
Holotype: HKAS 100725
Etymology: “krabiense” referring to collecting site.
Saprobic on decaying wood in a freshwater stream. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, white. Mycelium composed of partly immersed, partly superficial, hyaline to pale brown, septate, branched hyphae, with masses of crowded, glistening conidia. Conidiophores macronematous, mononematous, cylindrical, unbranched, septate, 45–140 μm long, 5–6.5 μm wide, brown, smooth-walled. Conidiogenous cells holoblastic, mono- to polyblastic, integrated, sympodial, terminal or intercalary, cylindrical, 12–18 μm long, 5–6 μm wide, brown, with hyaline denticles, smooth-walled. Conidia solitary, acropleurogenous, helicoid, rounded at tip, 30–40 μm diam. and conidial filament 3–4 μm wide (x̄ = 35 × 3.5 μm, n = 20), 230–320 μm long, tightly coiled 2½–3½ times, becoming loosely coiled in water, indistinctly multi-septate, guttulate, hyaline, smooth-walled. (Description from Lu et al. 2018)
Culture characteristics: Conidia germinating on water agar and germ tubes produced from conidia within 12 h. Colonies growing on PDA, irregular, with umbonate surface, wrinkled, edge undulate, reaching 9 mm in 2 weeks at 28 °C, brown to dark brown in PDA medium. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth.
Material examined: THAILAND, Krabi, Muang, Nongtalay, Khao Hang Nak, on decaying wood in a freshwater stream, 16 December 2015, Saranyaphat Boonmee, HN05–3 (HKAS 100725, holotype), ex-type living culture, MFLUCC 16–0224.
Notes: Morphologically, Neohelicosporium krabiense is most similar to N. acrogenisporum in shape of conidia and conidiophores but can be distinguished by its smaller-sized conidia. Phylogenetically, N. krabiense shares a sister relationship to Neohelicosporium sp. (CBS 189.95) and Neohelicosporium sp. (HKUCC 10235). We could not compare their morphology because the latter two lack morphological information, but phylogeny indicates that they are distinct species. Therefore, N. krabiense is identified as a new species in this study. (Notes from Lu et al. 2018)
Freshwater distribution: Thailand (Lu et al. 2018)