Paraophiobolus arundinis Phukhamsakda, Phookamsak Wanas., E. Camporesi & K.D. Hyde, sp. nov. Index Fungorum number: IF553921
Etymology: The epithet ‘‘arundinis’’ refers to the host, Arundo.
Saprobic on Arundo pliniana Turra. Sexual morph: Ascomata 170–410 μm high (including neck), 110–400 μm diam., immersed to erumpent through epidermis of host, light brown at base, brown to dark brown towards the apex, scattered, solitary to gregarious, globose to subglobose, uni-loculate, glabrous, ostiolate, papillate. Papilla 70–85 μm high, 60–80 μm diam., mammiform to oblong, with rounded to truncate apex, composed of several layers of dark brown to black cells, arranged in a textura angularis to textura prismatica, glabrous, ostiole central, without periphyses. Peridium 13–19(–24) μm wide, up to 40 μm, wide at the apex, thick-walled, outer layer composed of 5–7 layers of brown to dark brown, thick-walled cells, arranged in a textura angularis, inner layer composed of 3–4 layers of hyaline, thin-walled cells of textura angularis. Hamathecium comprising numerous, 1.5–5 μm wide, broad, branched, septate, cellular pseudoparaphyses, embedded in a gelatinous matrix. Asci 75–110 9 7–12 μm (x = 90 x 9 μm, n = 40), 8-spored, bitunicate, cylindrical to cylindrical-clavate, with short furcate pedicel, apically rounded, ocular chamber clearly visible when immature. Ascospores 70–85 9 2.5–3 μm (x = 78 9 3 μm, n = 30), fasciculate, scolecosporous, fifiliform, with rounded ends, tapered towards the lower cells, hyaline to pale yellowish when young, becoming yellowish green at maturity, slightly curved near the apex, with 12(–16) septa, swollen near the base of the 4th cell, slightly constricted at the 4th septum, not constricted at the other septa, not separating into part spores, smooth-walled, with terminal appendages at both ends. Asexual morph: Undetermined.
Culture characteristics: Colonies on PDA reaching 55–60 mm diam. after 4 weeks at 25–30 C, medium dense, circular, flflattened, surface smooth, with edge entire, fairly flfluffy to flfloccose, colony from above white to cream, colony from below, yellowish, produced yellow pigment in agar.
Material examined: ITALY, Province of Forlı`-Cesena [FC], Tontola—Predappio, on dead stem of Arundo pliniana Turra. (Poaceae), 1 July 2014, E. Camporesi, IT 1973 (MFLU 17-0930, holotype), ex-type living culture, MFLUCC 17-1789 = KUMCC 17-0163.
Notes: Paraophiobolus arundinis is similar to Ophiobolus niesslii in having yellowish, 12(–16)-septateascospores, swollen near the base of the 4th cell and with terminal appendages at both ends (Shoemaker 1976). However, O. niesslii varies in ascospore septation based on the descriptions of various authors [11(–12) septa in Shoemaker (1976), 15 septa in Saccardo (1883)]. Ophiobolus niesslii was transferred to Nodulosphaeria as Nodulosphaeria niesslii (Ba¨umler) L. Holm by Holm (1957). However, the species was reinstated and treated as a homonym of Ophiobolus incomptus (Carestia & De Not.) Sacc. (Shoemaker 1976; Index Fungorum 2017). The type specimen is available in S as Ophiobolus incomptus Niessl ex Linh., but we are unable to examine it. However, the morphological characters of our species were compared with the description of Ophiobolus niesslii, in Saccardo (1891) and Shoemaker (1976). Paraophiobolus arundinis differs from Ophiobolus niesslii in having smaller asci and ascospores and fewer septa in the ascospores (Saccardo 1891). Therefore, a new species Paraophiobolus arundinis is introduced with phylogenetic support as well. Multigene phylogenetic analyses showed that P. arundinis forms a sister clade with P. plantaginis with high support (100% ML, 99% MP, 1.00 PP). Paraophiobolus arundinis differs from P. plantaginis in having more septa in the ascospores and terminal appendages (Hyde et al. 2017).
Hosts: Arundo pliniana Turra. (Poaceae)
FIG Paraophiobolus arundinis (MFLU 17-0930, holotype) a,b Appearance of ascomata on host surface. c Vertical section through ascoma. d Ostiole cannel e Section through peridium. f Cellular pseudoparaphyses. g–i Developing state of asci. j–l Developing state of ascospores. Scale bars: a = 500 μm, b = 200 μm, c = 100 μm, d = 50 μm, e–l = 20 μm