Aquatisphaeria thailandica W.L. Li, D.F. Bao & Jian K. Liu, 2021

Li, Wen-Li, Bao, Dan-Feng, Liu, Ning-Guo, Hyde, Kevin D. & Liu, Jian-Kui, 2021, Aquatisphaeria thailandica gen. et sp. nov. (Tetraplosphaeriaceae, Pleosporales) from freshwater habitat in Thailand, Phytotaxa 513 (2), pp. 118-128 : 122-124

Aquatisphaeria thailandica W.L. Li, D.F. Bao & Jian K. Liu , sp. nov. FIGURE. 2

MycoBank MB 839208

Etymology: —Referring to the country where the fungus was collected

Holotype: — MFLU 20-0687

Saprobic on submerged decaying wood in freshwater habitats. Asexual morph: Colonies on natural substratum effuse, scattered, dark brown to black. Mycelium 1–2 μm wide, partly immersed, partly superficial, septate, branched, smooth, sub-hyaline to light brown. Conidiophores 29–47 × 4–5 μm (x =36 × 4.5 μm, n = 15), macronematous, mononematous, solitary, cylindrical, straight or slightly curved, unbranched, 3–4-septate, brown, smooth, thick-walled, slightly tapering towards the apex, truncate at the apex. Conidiogenous cells monoblastic, determinate, integrated, terminal, subcrylindrical, brown. Conidia 36–50 × 30–47 μm (x = 43 × 38 μm, n = 30), acrogenous, solitary, subglobose or turbinate, broader in the upper part, thin-walled, internally composed of several columns of cells, subhyaline to pale olive green when young, dark brown when mature, muriform, dictyoseptate, smooth-walled, with 3–4 (mostly 4) cylindrical, upward, paler appendages arising from the conidial apex, 19–29 × 2–3 μm (x = 24 × 2.5 μm, n = 30), 1–2- septate, basal cell trapeziform 2.5–6 × 3–5.5 μm (x = 4 × 4 μm, n = 15), truncated at the base.

Culture characteristics: —Colonies growing on PDA, reaching 30 mm diam. after 4 weeks at 25 °C in dark, circular, grey to dark grey with a white edge, aerial mycelium dense, velvety, producing black oil drops on the surface, in reverse dark brown with entire margin.

Material examined: — Thailand, Nakhon Phanom Province, That Phanom District , on submerged decaying wood, 13 November 2017, D.F. Bao, B119 ( MFLU 20-0687 , holotype) ; ex-type living culture MFLUCC 21-0025 ; living culture DLUCC B151 .

Notes:— The phylogenetic result ( FIGURE. 1 ) showed that the new taxa ( Aquatisphaeria thailandica ) formed a distinct clade within Tetraplosphaeriaceae . It is phylogenetically close to Ernakulamia and Shrungabeeja . Aquatisphaeria is similar to the other genera in Tetraplosphaeriaceae in having monoblastic conidiogenous cells and solitary, subglobose or turbinate conidia with filiform or horn-like appendages. The genera Pseudotetraploa , Quadricrura , Tetraploa , and Triplosphaeria can be easily distinguished from Aquatisphaeria by the absence of conidiophores ( Tanaka et al. 2009). Ernakulamia has monotretic conidiogenous cells which differs from other genera of Tetraplosphaeriaceae including Aquatisphaeria ( Delgado et al. 2017) . Aquatisphaeria resembles Shrungabeeja in having monoblastic conidiogenous cells and macronematous conidiophores. However, conidiophores in Shrungabeeja are conspicuously longer than Aquatisphaeria of three to six times (Zhang et al. 2017, Dong et al. 2020).

Figures

FIGURE 1. Phylogenetic tree generated from maximum likelihood (ML) analysis based on combined LSU, ITS and SSU sequence data. ML bootstrap support values greater than 75% and Bayesian posterior probabilities (PP) greater than 0.95 are given above the nodes, branches with 100% ML BP and 1.0 PP are in thickened.Taxa representing by type speciments (or ex-type strains) are highlighted in bold. Newly generated sequences are indicated in red.The tree is rooted with Amniculicola immersa (CBS 123083) and A. parva (CBS 123092). The figures on the right side show the morphology of the type species in each genus.

FIGURE2. Aquatisphaeria thailandica (MFLU 20-0687, holotype) a–c. Colonies on woody subtrate. d–i. Conidia attached to conidiophores. j. Conidiogenous cell. k–n. Conidia. o. Upper view of the colony on PDA. p. Reverse view of the colony on PDA. Scale bars: d–i = 30 μm, j–n = 10 μm.