Neohelicascus aquaticus (H. Zhang & K. D. Hyde) W. Dong, K.D. Hyde & H. Zhang, comb. nov.

Index Fungorum number: IF557922; Facesoffungi num- ber: FoF09264; Fig. 81

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)

Freshwater distribution: China (Zeng et al. 2018; this study), Japan (Tanaka et al. 2015), Thailand (Zhang et al. 2013a)

Saprobic on decaying wood submerged in freshwa- ter. Sexual morph: Pseudostromata clustered, immersed, ampulliform, coriaceous, with ostiolate papilla, visible on the host surface as blackened ostiolar dots. Pseudoparaphy- ses 1–3 μm diam., abundant, cellular, hypha-like, hyaline, septate, embedded in a gelatinous matrix. Asci 90–120 × 14–21 μm (x̄ = 110 × 19 μm, n = 5), 8-spored, bitunicate, fissitunicate, clavate, pedicellate. Ascospores 20–23 × 8–10 μm (x̄ = 22 × 8.5 μm, n = 15), mostly biseriate, ellipsoi- dal, brown, 1-septate, slightly constricted at septum, asym- metrical, apical cell usually longer than basal cell, curved, thin-walled, smooth, with a deliquescing sheath. Asexual morph: Undetermined.

Culture characteristics: On PDA, colony circular, reach- ing 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 collec- tion 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. 2013a). However, we did not observe the 3-septate ascospores and asexual morph in culture.

Helicascus alatus was introduced by Zeng et al. (2018) based on multigene phylogenetic analysis and morphologi- cal characters. Zeng et al. (2018) considered that H. alatus differs from H. aquaticus in smaller ascomata, short pedi- cels and presence of a sheath. However, a comparion 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 supports these strains to be the same species (Fig. 84).

Fig. 81 Neohelicascus aquaticus (HKAS 102145). a, b Immersed pseudostromata with blackened ostiolar dots. c Pseudoparaphyses. d Bituni- cate 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

Fig. 84 Phylogram generated from maximum likelihood analysis of combined LSU, SSU, ITS and TEF sequence data for species of Morospha- eriaceae. Bootstrap values for maximum likelihood equal to or greater than 75% and Bayesian posterior probabilities equal to or greater than 0.95 are placed near the branches as ML/BYPP. Newly generated sequences are in red and ex-type strains are in bold. The new species intro- duced in this study are indicated with underline. Freshwater strains are indicated with a red letter “F”. The tree is rooted to Latorua caligans CBS 576.65 (Latoruaceae)