Rhytidhysteron neorufulum Thambug. & K.D. Hyde, Cryptog. Mycol. 37(1): 110 (2016)

Ren, Guang-Cong, Wanasinghe, Dhanushka N., Jeewon, Rajesh, Monkai, Jutamart, Mortimer, Peter E., Hyde, Kevin D., Xu, Jian-Chu & Gui, Heng, 2022, Taxonomy and phylogeny of the novel rhytidhysteron-like collections in the Greater Mekong Subregion, MycoKeys 86, pp. 65-85 : 65

Rhytidhysteron neorufulum Thambug. & K.D. Hyde, Cryptog. Mycol. 37(1): 110 (2016)

Figure 4

Description.

Saprobic on decaying wood of Tectona grandis . Sexual morph Hysterothecia 1400-2100 μm long, 350-500 μm high, 600-1000 μm diam. (x̄ = 1780 × 400 × 700 μm, n = 5), superficial, black, solitary to aggregated, coriaceous, smooth, elliptical or irregular in shape, elongated with a longitudinal slit. Exciple 75-115μm (x̄ = 90, n = 20) wide, composed of several layers of brown to dark brown, thick-walled cells of textura angularis. Hamathecium 2-3.5 μm wide, dense, septate pseudoparaphyses, constricted at the septum, filiform, pale-yellow pigmented, forming epithecium above the asci and enclosed in a gelatinous matrix. Asci 190-260 × 13-18 μm (x̄ = 230 × 16 μm, n = 10), 8-spored, bitunicate, clavate to cylindrical, with a short furcate pedicel, apically rounded, without a distinct ocular chamber. Ascospores 36-44 × 11-17 μm (x̄ = 41 × 13 μm, n = 30), uni-seriate, yellowish to brown, with 1-3-septa, ellipsoidal to fusiform, slightly rounded or pointed at both ends, constricted at the central septum, with granular appearance. Asexual morph Undetermined.

Habitat and distribution.

Bursera sp (Mexico), Hevea brasiliensis and Tectona grandis (Thailand) ( Thambugala et al. 2016; Cobos-Villagran et al. 2020; this study).

Material examined.

Thailand, Tak Province, Mogro District, Amphoe Umphang , on dead woods of Tectona grandis ( Lamiaceae ), 20-Aug-2019, G.C. Ren, T203 (HKAS 115534), living culture MFLUCC 21-0035 .

Notes.

Rhytidhysteron neorufulum was introduced by Thambugala et al. (2016) based on both morphological and phylogenetic analyses of a combined dataset of LSU, SSU and tef 1-α sequence data. Thambugala et al. (2016) accounted R. neorufulum (MFLUCC 13-0216) from decaying woody stems and twigs in Thailand. Our new collection shares similar morphology to that of the type description of Rhytidhysteron neorufulum (MFLUCC 13-0216) in having superficial, coriaceous, elliptical or irregular, elongated hysterothecia with a longitudinal slit, bitunicate, cylindrical, short furcate pedicel asci and yellowish to brown, ellipsoidal to fusiform ascospores with 1-3-septa ( Thambugala et al. 2016). However, our new collection has larger asci (190-260 × 13-18 μm vs 185-220 × 9.5-13 μm) and ascospores (36-44 × 11-17 μm vs 19-31 × 8-13 μm) in comparison to the type of Rhytidhysteron neorufulum (MFLUCC 13-0216). The multi-gene phylogenetic analysis based on combined SSU, LSU, ITS, and tef 1-α sequence data showed that our collection is related to Rhytidhysteron neorufulum (Figure 1 ).

Figures

Figure 1. RAxML tree based on a combined dataset of partial SSU, LSU, ITS, and tef 1 - α sequence analyses. Bootstrap support values for ML and MP equal to or higher than 75 % and Bayesian PP equal to or greater than 0.95 are shown at the nodes. Hyphens (--) represent support values less than 75 % / 0.95 BYPP. The ex-type strains are in bold and the new isolate in this study is in blue. The tree is rooted with Gloniopsis calami (MFLUCC 15 - 0739) and G. praelonga (CBS 112415).

Figure 4. Rhytidhysteron neorufulum (HKAS 115534) a, b Hysterothecium on wood c vertical section through hysterothecia d exciple e pseudoparaphyses f-h immature asci and mature asci i-m immature ascospores and mature ascospores n germinating ascospore o, p culture characters on PDA (o = above view, p = reverse view). Scale bars: 1000 μm (a, b); 200 μm (c); 15 μm (d); 20 μm (e); 50 μm (f-h); 10 μm (i-m); 20 μm (n); 20 mm (o, p).