Kirschsteiniothelia septemseptatum S. Wang, Q. Zhao & K.D. Hyde, sp. nov.

Index Fungorum number: IF 559762; MycoBank number: MB 559762; Facesoffungi number: FoF 11800; Fig. 1

Etymology – Referring to the number of septa mostly observed in conidia

Holotype – MFLU 21–0126

Saprobic on decaying wood. Sexual morph: Not oberved. Asexual morph: Colonies on natural substrate, scattered or fascicular, effuse, hairy, dark brown to black, glistening. Mycelium partly superficial, partly immersed in the host tissue, composed of smooth, light brown, branched, septate. Conidiophores macronematous, mononematous, single to loosely fasciculate, erect, straight to slightly flexuous, branched at the apex, dark brown, multiseptate, 9–16 septate, 250–580 µm (x̄=415 µm, n=20) long, 6.5–14.5 μm (x̄= 10 µm, n = 20) wide. Conidiogenous cells mostly polytretic, sometimes monotretic, integrated, discrete, terminal and lateral, calyciform, 2 septate, 9.5–21 µm (x̄=16 µm, n=20) long, 4–8 μm (x̄=6 µm, n=20) wide. Conidia acrogenous, solitary, dry, olivaceous brown to brown, pale at apex, obclavate, rostrate, smooth, straight or curved, truncate at base, 5–8– euseptate, 25–55 μm (x̄=41 µm, n=20) long, 6.5–12.5 µm (x̄ =10.5 μm, n=20) wide.

Material examined – Thailand, ChiangMai Province, saprobic on decaying wood at MRC, July 2020, Song Wang, SW212, (MFLU 21–0126, holotype)

GenBank numbers – ON980757 (LSU); ON980752 (SSU); OP120779 (ITS); OP009581 (rpb2)

Notes – Kirschsteiniothelia septemseptatum shares similar characteristics with K. fluminicola in having macronematous, unbranched, cylindrical, septate, conidiophores and solitary, obclavate, septate, conidia. However, K. cangshanensis differs from K. fluminicola in having a gelatinous rounded sheath at the apex of shorter and thinner conidia (33–43×7.5–8.5 μm vs 47.5–86.5×8–10 μm). In our phylogetic analyses, K. septemseptata forms an independent branch with 91ML/95MP/1.00BYPP support (Fig. 2)

Figure 1 – Kirschsteiniothelia septemseptatum (MFLU 21–0126, holotype) a–c Colonies on dead wood. d, e Conidiophore with conidia. f–h Conidiogenous cells and conidia. i–m Conidia. n Germinating conidium. Scale bars: a=500 μm, b=200 μm, c=50 μm, d, e=100 μm, f–n=20 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined LSU, SSU, ITS sequence data. Forty-six taxa were included in the combined analyses, which comprised 2,104 characters (LSU=1–788 bp, SSU=789–1,632 bp, ITS=1,633–2,104 bp), including alignment gaps. Among them, 1,191 characters were constant, 239 characters were singleton sites, and 674 characters were parsimony informative. The best scoring RA×ML tree is presented. Bootstrap support values for ML and MP≥75% and BYPP≥0.95 are given above the nodes. Pseudorobillarda eucalypti (MFLUCC 12–0422) and P. phragmitis (CBS 398.61) were used as the outgroup taxa. The newly generated sequences are indicated in red. The ex-type strains are indicated in bold