Neohelicomyces hyalosporus

Neohelicomyces hyalosporus Y.Z. Lu, J.C. Kang & K.D. Hyde

Index Fungorum number: IF 554866; Facesoffungi number: FoF 04735

Holotype: HKAS 97441

Etymology: “hyalosporus” referring to hyaline helicospores of this fungus.

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, 210–290 μm long, 3–4 μm wide, hyaline to pale brown, smooth-walled. Conidiogenous cells holoblastic, mono- to polyblastic, integrated, sympodial, terminal or intercalary, cylindrical, with denticles, 9–20 μm long, 3–4 μm wide, hyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, rounded at tip, 14–20 μm diam. and conidial filament 1.5–2.5 μm wide (x̄ = 17 × 2 μm, n = 50), 120–140 μm long, tightly coiled 2½–3¾ 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, circular, with umbonate surface, veined and wrinkle, edge entire, reaching 12 mm in 2 weeks at 28 °C, brown in PDA medium. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth.

Material examined: CHINA, Guangxi Province, Fangchenggang City, on submerged decaying wood in a freshwater stream, 14 May 2016, Yong-Zhong Lu, PF11–1 (HKAS 97441, holotype; GZAAS 16–0098, isotype), ex-type living culture, GZCC 16–0086.

Notes: Neohelicomyces hyalosporus morphologically resembles Neohelicomyces pallidus (Linder 1929; Goos1989; Zhao et al. 2007, as Helicosporium pallidum) in conidiophores and conidiogenous cells as well as conidia. We could not distinguish them based on morphological characters. However, phylogenetically, N. hyalosporus is nested in between N. grandisporus and N. pallidus but without bootstrap support. Following the recommendation of Jeewon and Hyde (2016) for delimitation of new species, we looked into pair wise dissimilarities of DNA sequences and noted that there are 37 and 4 noticeable nucleotide differences in ITS and LSU sequence data respectively between our new isolate GZCC 16–0086 and N. pallidus (CBS 962.69), which indicates that they are distinct species. Therefore, Neohelicomyces hyalosporus sp. nov. is introduced here. (Notes from Lu et al. 2018)

Freshwater distribution: China (Lu et al. 2018)