Aquapteridospora lignicola J. Yang, K.D. Hyde & Maharachch., in Yang, Maharachchikumburaa, Hyde, Bhat, McKenzie, Bahkali, Gareth Jones & Liu, Cryptog. Mycol. 36(4): 474 (2015)

Index Fungorum Number: IF 551732; Facesoffungi number: FoF01641

Etymology – From lignicola meaning “dwelling on wood”

Saprobic on decaying plant substrates. Asexual morph: Colonies on the natural substrate effuse, hairy, dark brown. Mycelium superficial or partly immersed, composed of branched, septate, pale brown to brown, smooth, thin-walled hyphae. Conidiophores 70–200 × 4–7 μm (x̄ = 146 × 6 μm, n = 20), macronematous, mononematous, solitary, erect, straight or slightly flexuous, unbranched, cylindrical, septate, smooth, thick-walled, dark brown at the base, paler towards the apex. Conidiogenous cells polyblastic, terminal, becoming intercalary, pale brown, integrated, with several sympodial proliferations, bearing tiny, protuberant, circular scars. Conidia solitary, fusiform, smooth, obtuse at both ends, 3-euseptate, slightly constricted at septa, with pale to dark brown central cells and subhyaline end cells, guttulate, acropleurogenous, sometimes with a conspicuous sheath, 15–24 × 6–8 μm (x̄ = 21 × 7 μm, n = 45). Conidial secession schizolytic. Sexual morph: Undetermined.

Culture characters – Conidia germinating on PDA within 24 h and germ tubes produced from both ends. Colony on MEA slow-growing, reaching 5-10 mm diam. at 14 days, with dense white mycelium on the surface, in the center becoming sparse and dark brown at the edge; in reverse, with white middle and dark brown, smooth margin. After 2 months of incubation, the colony on MEA contained only superficial, branched, septate, smooth, mycelia and produced the asexual morph. habitat and distribution: On submerged wood in freshwater, Thailand.

Material examined – Thailand, Chiang Rai Province, a stream flowing in Tham Luang Nang Non-Cave, on submerged wood, 25 November 2014, Jing Yang (MFLU 15-1172, holotype), extype living culture, MFLUCC 15-0377, GZCC 15-0051.

Notes – Aquapteridospora lignicola most closely resembles Minimelanolocus manifestus (Hernández-Restrepo et al., 2012) and Pleurophragmium indicum (D’Souza & Bhat 2012). Minimelanolocus manifestus has cymbiform to subfusiform conidia, which are fimbrillate at the base and lack a sheath (Hernández-Restrepo et al. 2012), while pleurophragmium indicum has ellipsoidal to obovoid conidia, with dark brown central cells and pale brown end cells and lacks a sheath (D’Souza & Bhat 2012). Conidiogenous cells of Aquapteridospora lignicola are similar to Minimelanolocus manifestus but differ from the minutely denticulate conidiogenous cells of Pleurophragmium indicum. Molecular analysis confirms that the new genus cannot be placed in Minimelanolocus or Pleurophragmium, which belong to Dothideomycetes and Pezizomycotina, respectively. Aquapteridospora lignicola clusters in the Diaporthomycetidae and is close but distinct from Ellisembia and Sporidesmium.

Fig.  Aquapteridospora lignicola (MFLU 15-1172, holotype). a. Substrate. b–c. Colony on wood. d–e, g. Conidia on conidiophores. f, h. Conidiophores. i–k. Apices of the conidiophores show the conidiogenous cells and developing conidia. l–s. Conidia, some with mucilaginous sheath. t. Germinated conidium. u–v. Cultures on MEA, u from above, v from below. Scale bars: b = 200 μm, c = 50 μm, d, g–h, t = 30 μm, e-f = 40 μm, i = 15 μm, j–s = 10 μm.