Neoastrosphaeriella aquatica D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, 2019

Bao, Dan-Feng, Luo, Zong-Long, Jeewon, Rajesh, Nalumpang, Sarunyav, Su, Hong-Yan & Hyde, Kevin D., 2019, Neoastrosphaeriella aquatica sp. nov. (Aigialaceae), a new species from freshwater habitat in southern Thailand, Phytotaxa 391 (3), pp. 197-206 : 201

Neoastrosphaeriella aquatica D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su , sp. nov. Fig. 2

Index Fungorum number: IF 555357; Facesoffungi number: FoF 04910

Etymology:—referring to the aquatic habitat of this fungus.

Holotype: — MFLU 18–1392

Saprobic on decaying submerged wood in freshwater. Sexual morph: Ascomata 250–400 μm diam, 160–250 μm high (x = 352 × 208 μm, n = 8), black, carbonaceous, gregarious, scattered, papillate, broadly oblong with a flat top in frontal view, as dark spots on host surface, semi-immersed. Ostioles central, with carbonaceous, slit-like opening.

Peridium 20–50 μm wide, carbonaceous, dark brown, composed of cells of dark brown thick-walled textura angularis.

Pseudoparaphyses 0.8–2 μm wide, trabeculate, filiform, septate, hyaline, anastomosing and branched, embedded in a gelatinous matrix. Asci 84–112 × 14–19 μm (x = 98 × 15.7 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindricclavate or obclavate, with a short furcate pedicel, rounded at apex, with a shallow ocular chamber. Ascospores 31–37 × 5–8 μm (x = 34 × 6.4 μm, n = 30), overlapping, fusiform, tapering to pointed apices, hyaline when young, grayish brown and verrucose at maturity, 1-septate, slightly constricted at the septum, lacking guttules when young, with large guttules at maturity, surrounded by a thin, distinct mucilaginous sheath. Asexual morph: undetermined

Material examined: — THAILAND, Thanon Phetkasem, on submerged decaying wood, 1 September 2017, C.G.

Lin, 11F–1–1, B19, (MFLU 18–1392, holotype), ex-type living culture, MFLUCC 18–0209.

Notes: —In our phylogenetic analysis, our collection grouped in a well-supported clade with the type species N.

krabiensis and N. sribooniensis within Neoastrosphaeriella , and had a close affinity with N. krabiensis (100% ML and

MP, 1.00 PP, Fig. 1 ). We compared the TEF1-α sequence data of N. aquatica with N. sribooniensis and there are 16

base pair differences, which indicates that N. aquatica and N. sribooniensis are different. We also compared the base-

pair differences among ITS nucleotides of N. aquatica and N. krabiensis and found 1.48% differences. There are not enough DNA sequence data for N. krabiensis , so we cannot compare base pair differences in other genes.

Morphologically, the sexual morph of Neoastrosphaeriella aquatica is similar to N. krabiensis and N. sribooniensis in having bitunicate, obclavate, short pedicellate asci and similar shaped, 1-septate, ascospores slightly constricted at the septum, and surrounded by a thin, distinct sheath. However, N. krabiensis has brown, verrucose ascospores

( Liu et al. 2011), while Neoastrosphaeriella aquatica differs from N. krabiensis in having hyaline to grayish brown ascospores with large guttules. Ascospores of Neoastrosphaeriella aquatica differ from N. sribooniensis in having hyaline to grayish brown ascospores, smooth when young, verrucose at maturity and with large guttules, whereas in N.

sribooniensis ascospores are hyaline, smooth-walled, and lacking guttules ( Wanasinghe et al. 2018).

All species of Neoastrosphaeriella were reported on different hosts from terrestrial habitats. Neoastrosphaeriella krabiensis was collected on a petiole of Metroxylon sagu ; N. sribooniensis was collected on dead Calamus rotang stem

( Arecaceae ) and N. alankrithabeejae was collected on Calamus andamanicus from terrestrial habitats ( Liu et al. 2011, Wanasinghe et al. 2018, Niranjan & Sarma 2018). However, our new taxon, N. aquatica was collected on decaying submerged wood from freshwater habitat and this is the first report of a Neoastrosphaeriella species from freshwater habitat ( Liu et al. 2011, Wanasinghe et al. 2018).

Figures

FIGURE 1. Phylogenetic tree based on RAxML analyses of a combined ITS, LSU, SSU and TEF1-α dataset. Bootstrap support values for maximum parsimony (MP, blue) and maximum likelihood (ML, black) higher than 75% and Bayesian posterior probabilities (BYPP, red) greater than 0.95 are indicated above the nodes as MPBS / MLBS /PP. The tree is rooted with Hysterium angustatum CBS 123334 and CBS 236.34 (Hysteriaceae). The new isolate is in bold and red.

FIGURE 2 Neoastrosphaeriella aquatica (MFLU 18–1392, holotype). a–b. Ascomata on wood. c. Section of ascoma. d–e. Section of peridium. f. Pseudoparaphyses. g. ocular chamber. h–k. Asci. l–o. Ascospores. p. Ascospore in India Ink, with clear sheath. Scale bars: c = 50 μm, d–e, h–k = 20 μm, f–g, l–p = 10 μm.