Distoseptispora septata J Ma, K. D. Hyde & Y.Z. Lu, sp. nov. (Figure 7).

MycoBank number: MB; Index Fungorum number: IF; Facesoffungi number: FoF 11337;

Etymology: ‘septata’ referring to the ‘septate’ conidia.

Holotype: HKAS 123759

Saprobic on decaying wood submerged in freshwater habitats. Sexual morph: Undetermined. Asexual morph: hyphomycetous. Colonies on natural substrate superficial, effuse, gregarious, smooth, septate, hairy, brown or dark brown. Mycelium mostly immersed, composed of branched, septate, smooth, pale brown to brown hyphae. Conidiophores 23.3–85.5 μm × 3.0–6.9 μm ( = 44.1 × 5.7 μm, n = 30), macronematous, mononematous, cylindrical, erect, simple, mostly flexuous, unbranched, smooth, thick-walled, smooth-walled, solitary, brown, 1-6-septate. Conidiogenous cells 5.3–18.1 × 4.1–6.1 μm (x̅ = 9.0 × 5.0 μm, n = 30), holoblastic, monoblastic, terminal, integrated, cylindrical, pale brown or brown, smooth. Conidia 22.1–179.2 × 9.8–16.2 μm (x̅ = 89.1 × 13.4 μm, n = 35), acrogenous, solitary, multi-distoseptate and up to 25 septate, obclavate, rostrate, straight or slightly curved, verruculose, guttulate, thick-walled, smooth-walled, pale brown or dark brown, olivaceous-green, usually paler towards apex, rounded at apex, with a truncate base.

Culture characteristics: Conidia germinating on PDA within 12 h and germ tubes produced from conidia. Colonies growing on PDA, reaching 35 mm diam, after 25 days at 25°C, circular, flat, with dense, fluffy, olivaceous-green or paler brown mycelium at the center, dark brown at the entire margin; in reverse dark brown.

Material examined: China, Hainan Province, Wuzhishan National Nature Reserve, on decaying wood submerged in a freshwater stream, 26 December 2021, Xia Tang, W17 (HKAS 123759, holotype; GZAAS22-0083, isotype), ex-type living culture, GZCC22-0078.

GenBank accession numbers: (LSU), (ITS), (TEF1α) ON, (RPB2) ON.

Notes: Distoseptispora septata forms a sister clade to D. guizhouensis with relatively well-supported values (92% ML and 1 BYPP). However, D. septata differs from D. guizhouensis in having larger conidiophores [23.3–85.5 μm × 3.0–6.9 μm, 1–6-septate versus 21–50 μm × 4–9 μm] and smaller conidia [22.1–179.2 μm × 9.8–16.2 μm versus 90–273 μm × 15–21 μm]. Especially, D. guizhouensis can distinct with D. septata by its unique characters on flexuous conidiophores. Based on a pairwise nucleotide comparison of ITS, D. septata differs the D. guizhouensis in 13/ 535 bp (2.4%) for ITS. Following the guidelines of Jeewon & Hyde, we introduce our new species as a novel taxon within the Distoseptispora.

Figure 7. Distoseptispora septata (HKAS 123759, holotype) a–b Colonies on natural substrate. c–g Conidiophores, conidiogenous cells bearing conidia. h–j Conidia. k–l Conidiophores and conidiogenous cells. m Germinating conidium. n, o Culture on PDA from above and reverse. Scale bars: c–m = 20 μm