Thysanorea fusiformis W.P. Wang, H.W. Shen, K.D. Hyde & Z.L. Luo, in Wang, Hyde, Bao, Wanasinghe, Lin, Shen, Lu, Zhang, Su, Li, Al-Otibi, Yang & Luo, Mycosphere 15(1): 6581 (2024)

Index Fungorum number: IF902429; MycoBank number: MB902429; Facesoffungi number: FoF16103

Etymology – Referring to the fusiform conidia of this fungus.

Holotype – HKAS 131396

Saprobic on submerged decaying wood. Asexual morph: Colonies superficial, effuse, hairy, scattered, dark brown, with subhyaline, gathered, fusiform conidia on the apex of conidiophores. Mycelium mostly immersed, composed of septate, pale brown, smooth-walled hyphae. Conidiophores 180–300 × 4.8–8 µm (x̅ = 232.2 × 6.3 µm, n = 15), mononematous, macronematous, erect, unbranched, cylindrical, straight or slightly flexuous, septate, smooth, thick-walled, dark at base and middle, and gradually paler towards the apex, slightly attenuated and narrowing at apex. Conidiogenous cells polyblastic, integrated, terminal, sympodially proliferating, subhyaline to pale brown. Conidia 20–37 × 5.1–9.2 µm (x̅ = 29 × 6.7 µm, n = 40), acrogenous, fusiform, solitary, mostly straight, 3–4-septate, septum darker, partly slightly constricted at the septum, smooth-walled, subhyaline to pale brown, with a prominent hilum at the base. Sexual morph: Undetermined.

Culture characteristics – Conidia germinating on PDA within 12 h, and germ tubes produced from the both ends. Colonies on PDA reaching 30 mm diameter after 3 weeks at room temperature. Mycelium dry, dense, colonies on the surface of PDA, with regular edge, has a big bulbous protrusion in the center, celadon, velvety. Reverse dark green, smooth.

Material examined – China, Yunnan Province, Wenshan Zhuang and Miao Autonomous Prefecture, Bamei Town, on submerged decaying wood, 7 February 2022, W.P. Wang, S-3276 (HKAS 131396, holotype), ex-type living cultures CGMCC 3.25425 = KUNCC 23–13729.

Notes – In the phylogenetic analysis, Thysanorea fusiformis is sister to T. amniculi (Fig. 2). Thysanorea fusiformis and T. amniculi can be clearly distinguished from each other by the conidiophores and conidia. Thysanorea fusiformis has unbranched, shorter (180–300 vs. 190–465 µm) conidiophores, but larger (20–37 × 5.1–9.2 vs. (13–) 15–23 × 2.5–5 µm) and fusiform conidia (Yang et al. 2023). The comparison nucleotides of ITS and LSU sequences data indicated that T. fusiformis (CGMCC 3.25425) differs from T. amniculi (GZCC 20–0465) in 2.8% (16/572 bp) and 0.24% (2/826 bp), which strongly support T. fusiformis as a new species.

Figure 1 – Thysanorea fusiformis (HKAS 131396, holotype). a Colonies on the substratum. b, c, e Conidiophores with conidia. d Conidiophores. f Conidiogenous cell. g–k conidia. l Germinating conidium. m, n Colonies on PDA from surface and reverse. Scale bars: b–e = 50 µm, f = 20 µm, g = 30 µm, h–l = 15 µm.

Figure 2 – RAxML tree based on analysis of Herpotrichiellaceae that combined LSU, ITS, and SSU dataset. The combined analyses include 48 strains with 2355 characters, including gaps (LSU: 6584 857 bp, ITS: 556 bp, and SSU: 942 bp). Bootstrap support values for maximum likelihood (ML) greater than 75% and Bayesian posterior probabilities greater than 0.95 are indicated above branches as ML/PP. The tree is rooted with Cyphellophora oxyspora (CBS 698.73) and C. sessilis (CBS 243.85). The new collections are indicated in red. Ex-type strains are indicated with “T” after the strain number.