Thozetella nivea (Berk.) Kuntze, Revis. gen. pl. (Leipzig) 2: 873 (1891) Fig 37
Index Fungorum number: IF 144861; MycoBank number: MB 144861; Facesoffungi number: FoF 10601;
Basionym: Thozetia nivea Berk., J. Linn. Soc., Bot. 18: 388 (1881)
Saprobic on submerged decaying wood in freshwater. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies effuse, superficial, sessile sporodochial, cream white. Sporodochia 124–220 μm in diam. solitary, scattered, superficial, cylindrical or subulate, cream white to pale yellowish white, with a white spore mass at the apex. Microawns 25–45 µm long, 2.0–3 µm wide at the widest point (x̄ = 33.8 × 2.7 µm, n = 10), visible as small hairs on the sporodochial mass, hyaline, aseptate, smooth-walled, thick-walled, straight, sigmoid, curved. Conidiophores macronematous, synnematous, abundant, brown to dark brown, elongated, cylindrical, septate, smooth-walled. Conidiogenous cells 10–16 × 2.0–3.5 μm (x̄ = 13.4 × 2.8 μm, n = 20) monophialidic, hyaline, smooth-walled, irregularly subcylindrical, without collaretes. Conidia 15–20 × 1.5–3.5 μm (x̄ = 17.2 × 2.6 μm, n = 50), naviculate to fusiform or ellipsoid, with rounded ends, inequilateral, hyaline, smooth-walled, with a single filiform setula at each end, 6.0–9.0 × 0.45–0.75 μm (x̄ = 7.6 × 0.6 μm, n =50).
Culture characteristics – Conidia germinated on MEA within 24 h. Germ tubes arising from terminal ends of the conidia. Mycelia superficial, irregular, with entire edge, obverse pale reddish brown at the center then becoming yellowish brown at the margin, tufted colony center elevated, reverse dark brown at the center then becoming light yellowish brown at the margin.
Material examined – THAILAND, Tak Province, Tha Sing Yang, Ban Mae Ja Wang on decaying wood submerged in a freshwater river, 17 October 2019, N. Padaruth, CC60 (MFLU 21–**, holotype), ex-type living culture, MFLUCC 21–**.
GenBank submissions – LSU: **, ITS: **
Notes – The phylogenetic analysis of LSU and ITS sequence data shows that the isolate grouped within the Thozetella clade and clustered together with Thozetella nivea (GenBank numbers: EU825200, EU825201) (Fig. 33) Thozetella nivea CC60 has a smaller conidiomata (124–220 μm vs. 200–250 μm), smaller conidia (15–20 × 1.5–3.5 μm vs. 7.5–24 × 3–3.8 μm), and smaller microawns (25–45 × 2.0–3 µm vs. 50–70 × 1.3–4 µm) compared to the type description of T. nivea by Kuntze (1891). Thozetella nivea was previously reported by Sivichai et al. (2002) and Pinruan et al. (2014) from a freshwater habitat in Thailand but without morphological and molecular data, and the present collection suffice the lacking data of the Thailand strain.
Fig 37. Thozetella nivea (MFLU 21–**: New record). a–c Appearance of conidiomata on natural substrate. d Synnemata. e Conidiogenous cells. f–j Microawns. k–n Conidia. Scale bars: a = 1000 μm, b = 500 μm, c = 200 μm, d = 50 μm, e–n = 10 μm.