Fungalpedia – Note 2462, Neohelicascus
Neohelicascus W. Dong, H. Zhang, K.D. Hyde & Doilom
Citation when using this data: Dong W et al. 2020 – Fungalpedia, Ascomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1
Classification: Morosphaeriaceae, Pleosporales, Pleosporomycetidae, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi
Etymology: referring to its morphological similarity to Helicascus
Saprobic on submerged wood. Sexual morph: Pseudostromata scattered, comprising brown to black fungal material growing in cortex of host, unil- or multi-loculate, flattened at the basal region, horizontally arranged under the pseudostroma, visible on the host surface as blackened ostiolar dots. Locules immersed, lenticular to ampulliform, ostiolate. Ostiole converging at the centre, uniting into one common, central pore, periphysate. Peridium of locules comprising several layers of brown, thin-walled angular cells, paler inwardly, fusing with the host cells. Pseudoparaphyses numerous, cellular, hypha-like, hyaline, septate, embedded in a gelatinous matrix. Asci 8-spored, bitunicate, fissitunicate, clavate, long pedicellate, base of endoascus long, narrow and coiled within ectoascus, ectoascus uncoiling to form a long tail-like extension, apically rounded with a cylindrical ocular chamber. Ascospores mostly biseriate, straight or slightly curved, ellipsoidal to broadly fusiform, with rounded ends, 1-(2-3)-septate, apical cell slightly larger than basal cell, brown, thin-walled, smooth- or rough-walled, with or without a deliquescing sheath (Zhang et al. 2013a). Asexual morph: Coelomycetous. Pycnidia solitary, superficial, with the base immersed, uniloculate, globose to subglobose, brown, coriaceous, central ostiolate, with minute papilla. Peridium composed of brown, thin-walled cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells holoblastic, determinate, cylindrical to subcylindrical, hyaline, smooth. Conidia ellipsoid to obovoid, hyaline, aseptate, occasionally two-celled, smooth, thin-walled, without sheath or appendage (Zhang et al. 2013a).
Notes: Neohelicascus is introduced to accommodate the new species N. submersus H. Yang et al. and another seven new combinations as listed below. Neohelicascus is distinguished from Aquihelicascus in producing brown ascospores and the base of endoascus is long, narrow and coiled within ectoascus which uncoils to form a long tail-like extension. In contrast, Aquihelicascus possesses hyaline ascospores and an uncoiled endoascus. Phylogenetic analysis supports two genera, Aquihelicascus and Neohelicascus.
The ascospores of N. egyptiacus and N. elaterascus are surrounded by a defined gelatinous sheath, which is absent in N. unilocularis (Zhang et al. 2013a, 2015). Neohelicascus gallicus is surrounded by some fugacious mucilaginous remnants, but only seen in ascospores that are just released from the asci (Zhang et al. 2014b). Neohelicascus aquaticus was characterized by 1-(2- or 3-) septate ascospores with a deliquescing sheath (Zhang et al. 2013a), although Tanaka et al. (2015) observed only 1-septate ascospores without a sheath from a Japanese collection. Neohelicascus aquaticus is the only species producing asexual morph in culture (Zhang et al. 2013a).
Type species: Neohelicascus aquaticus (Huang Zhang & K. D. Hyde) W. Dong & H. Zhang
Other accepted species: Species Fungorum – search Neohelicascus.
Figure 1 – Neohelicascus aquaticus (HKAS 102145). a, b Immersed pseudostromata with blackened ostiolar dots. c Pseudoparaphyses. d Bitunicate ascus. e, f Ascospores. g, h Colony on PDA (up-front, down-reverse). Scale bars: c, f = 10 μm, d = 30 μm, e = 20 μm.
References
Entry by
Wei Dong, Faculty of Agriculture and Food, Kunming University of Science and Technology, Kunming 650500, China, Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand, Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, Institute of Plant Health, Zhongkai University of Agriculture and Engineering, Haizhu District, Guangzhou 510225, China
Published online 15 May 2026