Roussoella neopustulans D.Q. Dai, J.K. Liu & K.D. Hyde, 2014

Liu, Jian-Kui, Phookamsak, Rungtiwa, Dai, Dong-Qin, Tanaka, Kazuaki, Jones, Gareth, Xu, Jian-Chu, Chukeatirote, Ekachai & Hyde, Kevin D., 2014, Roussoellaceae, a new pleosporalean family to accommodate the genera Neoroussoella gen. nov., Roussoella and Roussoellopsis, Phytotaxa 181 (1), pp. 1-33 : 15

Roussoella neopustulans D.Q. Dai, J.K. Liu & K.D. Hyde , sp. nov. FIG. 8

Index Fungorum : IF550664

Etymology. Similar to the species Roussoella pustulans , but ascospores are smaller.

Saprobic on decaying bamboo culms. Ascostromata 0.5−1 mm diam, forming under raised, visible, black, dome-shape areas on host surface and becoming tumefied on maturity. Locules 70−100 µm high, 250−400 µm diam., solitary to gregarious, subglobose to ellipsoidal, dark brown, with an inconspicuous central ostiole. Peridium comprising host and fungal tissues, thin, 7−10 µm wide, composed of dark brown cells of textura angularis. Hamathecium comprising 1−1.5 µm wide, numerous, anastomosing branched cellular pseudoparaphyses, rough-walled, and embedded in a gelatinous matrix. Asci 80−95(−101) × 5.5−6.5 µm (x = 87.5 × 6.7 µm, n = 20), 6−8-spored, bitunicate, cylindrical, with a short knob-like pedicel, with an ocular apical chamber. Ascospores (8−)11−12.5(−14) × (7−)3.5−4.5 µm (x = 11.5 × 4 µm, n = 30), uni-seriate, ellipsoid to broad fusiform, 2-celled, upper cells bigger, occasionally curve, constricted at the septum, narrowly at both ends, with longitudinal striations. Asexual morph not produced in culture.

Specimen examined THAILAND, Chiang Rai Province, Mae Fah Luang University, on dead culm of Bamboo , 1 August 2011, D. Q . Dai, DDQ0090 (holotype MFLU 13−0639 , ex-type living culture MFLUCC 11−0609 ) .

Notes: Roussoella neopustulans is morphogically similar to R. pustulans , but differs in having smaller ascospores (11−12.5 × 3.5−4.5 µm vs. 10–16 × 4–5 µm) and larger asci (80−95 × 5.5−6.5 µm vs. 68–83 × 6.5–8.5 µm). In R. neopustulans the ascospore striations extend along the entire length and are linear, while those in R. pustulans are shorter and irregular ( Hyde 1997). Roussoella neopustulans is phylogenetically distinct ( FIGS. 1, 2) from R. pustulans ( MAFF 239638). Roussoella neopustulans is also a phylogenetically distinct from R. siamensis ( FIGS. 1, 2), but they are difficult to distinguish morphologically.

Figures

FIGURE 8. Roussoella neopustulans. a. Ascostromata on bamboo culm; b. Section of ascostroma; c. Peridium; d. Pseudoparaphyses; e−h. Asci; i−m.Ascospores; n. Geminating ascospore; o, p. Culture on PDA from after 20 days. ─ Scale bars: a =500 μm; b =100μm; c−n =10 μm; o, p = 30 mm.