Anastomitrabeculia didymospora Bhunjun, Phukhams and K.D. Hyde, in Bhunjun, Phukhamsakda, Jeewon, Promputtha & Hyde, Journal of Fungi 7(2, no. 94): 12 (2021)
MycoBank number: MB 556559; Index Fungorum number: IF 556559; Facesoffungi number: FoF 09523; Figure 3.
Etymology: Referring to the didymosporous ascospores.
Holotype–MFLU 20-0694.
Saprobic on dead bamboo culms submerged in freshwater. Sexual morph: Ascomata 430–460 µm high, 435–575 µm diam., immersed under a clypeus to semi-immersed, gregarious, uniloculate, globose to subglobose, carbonaceous, rough, black, ostiolate. Ostiole 160 µm high, 270 µm diam., central, apex well developed, papillate, with pore-like opening, with periphyses filling the ostiolar canal, dark brown to black, orange pigment near ostiole. Peridium 6–18 µm wide, comprising 3–5 layers of brown to hyaline cells of textura angularis, inner layers composed of thin, hyaline cells. Hamathecium of dense, long, 0.8–1.25 µm wide (x = 1 µm, n = 50), filiform, filamentous, trabeculate pseudoparaphyses, septate, branched, embedded in a gelatinous matrix, anastomosing between the asci and at the apex. Asci 125–160 15–20 µm (x = 145 17 µm, n = 20), 8–spored, bitunicate, fissitunicate, broad cylindrical to cylindrical-clavate, with bulbous pedicellate, rounded at the apex, with an ocular chamber. Ascospores 18–28 7–10 µm (x = 22.5 9 µm, n = 20), biseriate, broadly fusiform, tapering towards the ends, hyaline, 1-septate at the centre, constricted at the septum, cell above septate enlarged, straight, smooth-walled, with longitudinally striate wall ornamentation, surrounded by a mucilaginous sheath. Asexual morph: Undetermined.
Culture characters: Ascospores germinating on MEA and PDA within 24 h with germ tubes developing from basal cells. Colonies on MEA and PDA umbonate at the centre, circular, friable, reaching 20 mm diameter after four weeks of incubation at 25 ◦C. Culture on MEA with white aerial mycelium, dark brown at the centre and paler towards the edge from above and below. Culture on PDA dark brown from above and below.
Material examined: THAILAND, Krabi province (8.1◦ N, 98.9◦ E), on dead bamboo culms, 15 December 2015, C. Phukhamsakda, KR001 (MFLU 20-0694, holotype), ibid, 18 December 2015 (MFLU 20-0695, paratype); ex-type living culture MFLUCC 16-0412; ex-paratype living culture, MFLUCC 16-0417.
Figure 3. Anastomitrabeculia didymospora (MFLU 20-0694, holotype). (a) Ascomata on bamboo. (b) Close-up of ascomata. (c) Vertical section of ascoma. (d) Ostiolar canal. (e) Peridium layer. (f) Trabeculate pseudoparaphyses. (g–i) Asci. (j) Pedicel. (k–o) Ascospores showing mucilaginous sheath. (p) Culture characteristics on PDA from above and below (9 cm diameter petri dish). Scale bar: (b) = 500 µm, (c) = 200 µm, (d–i) = 50 µm, (j–o) = 10 µm.