Neohelicascus aquaticus (H. Zhang & K. D. Hyde) W. Dong, K.D. Hyde & H. Zhang
Index Fungorum number: IF557922; Facesoffungi number: FoF09264
Basionym: Helicascus aquaticus H. Zhang & K.D. Hyde, Sydowia 65(1): 155 (2013)
Synonymy: Helicascus alatus M. Zeng, S.K. Huang, Q. Zhao & K.D. Hyde, Phytotaxa 351(3): 215 (2018)
Saprobic on decaying wood submerged in freshwater. Sexual morph: Pseudostromata clustered, immersed, ampulliform, coriaceous, with ostiolate papilla, visible on the host surface as blackened ostiolar dots. Pseudoparaphyses 1–3 μm diam., abundant, cellular, hypha-like, hyaline, septate, embedded in a gelatinous matrix. Asci 90–120 × 14–21 μm ( = 110 × 19 μm, n = 5), 8-spored, bitunicate, fissitunicate, clavate, pedicellate. Ascospores 20–23 × 8–10 μm ( = 22 × 8.5 μm, n = 15), mostly biseriate, ellipsoidal, brown, 1-septate, slightly constricted at septum, asymmetrical, apical cell usually longer than basal cell, curved, thin-walled, smooth, with a deliquescing sheath. Asexual morph: Undetermined. (Description from Dong et al. 2020)
Culture characteristics: On PDA, colony circular, reaching 40 mm in 50 days at 25 °C, reddish brown to black from above, reddish brown from below, surface rough, dry,
umbonate, edge entire.
Material examined: CHINA, Yunnan Province, Qujing, on submerged wood in a stream, 10 May 2017, C.X. Liu, L25 (HKAS 102145), living culture KUMCC 19-0107.
Notes: The LSU and ITS sequence data from our collection HKAS 102145 shows 100% identity with the sequences of Helicascus aquaticus (MFLUCC 10-0918). HKAS 102145 fits well with the morphological features of H. aquaticus (Zhang et al. 2013). However, 3-septate ascospores and asexual morph in culture was not observed by Dong et al. (2020). Helicascus alatus was introduced by Zeng et al. (2018) based on multigene phylogenetic analysis and morphological characters. Zeng et al. (2018) considered that H. alatus differs from H. aquaticus in smaller ascomata, short pedicels and presence of a sheath. However, a comparison of nucleotides shows that H. alatus (MFLUCC 17-2300) and H. aquaticus (MFLUCC 10-0918) have identical sequences in LSU and ITS sequence data. Additionally, there are only two nucleotide differences in TEF sequence data between H. alatus (MFLUCC 17-2300) and H. aquaticus (MAFF 243866), thus H. alatus is a synonymy of H. aquaticus. Phylogenetic analysis of Dong et al. (2020) supports these strains to be the same species. (Notes from Dong et al. 2020)
Freshwater distribution: China (Zeng et al. 2018; Dong et al. 2020), Japan (Tanaka et al. 2015), Thailand (Zhang et al. 2013)
Fig 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
Dong W, Wang B, Hyde KD, McKenzie EHC, Raja HA, Tanaka K, Abdel-Wahab MA, Abdel-Aziz FA, Doilom M, Phookamsak R, Hongsanan S, Wanasinghe DN, Yu XD, Wang GN, Yang H, Yang J, Thambugala KM, Tian Q, Luo ZL, Yang JB, Miller AN, Fournier J, Boonmee S, Hu DM, Nalumpang S, Zhang H (2020) Freshwater Dothideomycetes. Fungal Divers 105:319–575. https://doi.org/10.1007/s13225-020-00463-5
Tanaka K, Hirayama K, Yonezawa H, Sato G, Toriyabe A, Kudo H, Hashimoto A, Matsumura M, Harada Y, Kurihara Y (2015) Revision of the Massarineae (Pleosporales, Dothideomycetes). Stud Mycol 82:75–136
Zeng M, Huang SK, Hyde KD, Zhao Q (2018) Helicascus alatus (Morosphaeriaceae), a new freshwater species from southwestern China. Phytotaxa 351:210–218
Zhang H, Hyde KD, Abdel-Wahab MA, Abdel-Aziz FA, Ariyawansa HA, Ko TWK, Zhao RL, Alias SA, Bahkali AH, Zhou D (2013) A modern concept for Helicascus with a Pleurophomopsis-like asexual state. Sydowia 65:147–166