Neohelicascus aquaticus 2020

Neohelicascus aquaticus (H. Zhang & K. D. Hyde) W. Dong, K.D. Hyde & H. Zhang, comb. nov.2020

Index Fungorum number: IF557922; Facesoffungi number: FoF09264;

Holotype: CHINA, Yunnan Province, Qujing, on submerged wood in a stream, 10 May 2017, C.X. Liu, L25 (HKAS 102145), living culture KUMCC 19-0107

Morphological description

 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 ( ^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, 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.

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.Asexual morph: Undetermined.Culture characteristics: On PDA, colony circular, reaching 5 mm in 15 days at 25 °C, white to grey from above, brown from below, surface rough, fluffy, with dense mycelium, dry, raised, edge entire.

Habitat: submerged wood

Distribution: CHINA

GenBank Accession:

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. 2013a). However, we did not observe the 3-septate ascospores and asexual morph in culture.

Reference: Freshwater Dothideomycetes are a highly diverse group of fungi, which are mostly saprobic in freshwater habitats worldwide. They are important decomposers of submerged woody debris and leaves in water. In this paper, we outline the genera of freshwater Dothideomycetes with notes and keys to species. Based on multigene analyses and morphology, we introduce nine new genera, viz. Aquimassariosphaeria, Aquatospora, Aquihelicascus, Fusiformiseptata, Neohelicascus, Neojahnula, Pseudojahnula, Purpureofaciens, Submersispora; 33 new species, viz. Acrocalymma bipolare, Aquimassariosphaeria kunmingensis, Aquatospora cylindrica, Aquihelicascus songkhlaensis, A. yunnanensis, Ascagilis submersa, A. thailandensis, Bambusicola aquatica, Caryospora submersa, Dictyocheirospora thailandica, Fusiformiseptata crocea, Helicosporium thailandense, Hongkongmyces aquaticus, Lentistoma aquaticum, Lentithecium kunmingense, Lindgomyces aquaticus, Longipedicellata aquatica, Neohelicascus submersus, Neohelicomyces dehongensis, N. thailandicus, Neohelicosporium submersum, Nigrograna aquatica, Occultibambusa kunmingensis, Parabambusicola aquatica, Pseudoasteromassaria aquatica, Pseudoastrosphaeriella aquatica, Pseudoxylomyces aquaticus, Purpureofaciens aquatica, Roussoella aquatica, Shrungabeeja aquatica, Submersispora variabilis, Tetraploa puzheheiensis, T. yunnanensis; 16 new combinations, viz. Aquimassariosphaeria typhicola, Aquihelicascus thalassioideus, Ascagilis guttulaspora, A. queenslandica, A. seychellensis, A. sunyatsenii, Ernakulamia xishuangbannaensis, Neohelicascus aquaticus, N. chiangraiensis, N. egyptiacus, N. elaterascus, N. gallicus, N. unilocularis, N. uniseptatus, Neojahnula australiensis, Pseudojahnula potamophila; 17 new geographical and habitat records, viz. Aliquandostipite khaoyaiensis, Aquastroma magniostiolata, Caryospora aquatica, C. quercus, Dendryphiella vinosa, Ernakulamia cochinensis, Fissuroma neoaggregatum, Helicotruncatum palmigenum, Jahnula rostrata, Neoroussoella bambusae, N. leucaenae, Occultibambusa pustula, Paramonodictys solitarius, Pleopunctum pseudoellipsoideum, Pseudocapulatispora longiappendiculata, Seriascoma didymosporum, Shrungabeeja vadirajensis and ten new collections from China and Thailand, viz. Amniculicola guttulata, Aquaphila albicans, Berkleasmium latisporum, Clohesyomyces aquaticus, Dictyocheirospora rotunda, Flabellascoma fusiforme, Pseudoastrosphaeriella bambusae, Pseudoxylomyces elegans, Tubeufa aquatica and T. cylindrothecia. Dendryphiella phitsanulokensis and Tubeufa roseohelicospora are synonymized with D. vinosa and T. tectonae, respectively. Six orders, 43 families and 145 genera which belong to freshwater Dothideomycetes are reviewed. Of these, 46 genera occur exclusively in freshwater habitats. A world map illustrates the distribution of freshwater Dothideomycetes

Fig. 81  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 an uncoiled endoascus. Phylogenetic analysis supports two genera, Aquihelicascus and Neohelicascus