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

Index Fungorum number: IF559763; MycoBank number: MB 559763; Facesoffungi number: FoF 11801; Fig. 1

Etymology – Referring to the long conidia

Holotype – MFLU 21-0128

Saprobic on decaying wood. Sexual morph: Not oberved. Asexual morph: Colonies effuse on natural substrate, scattered or fascicular, hairy, black, glistening. Mycelium partly immersed, partly superficial in the substrate, composed of pale brown, ranched hyphae. Conidiophores macronematous, mononematous, solitary or sometimes caespitose, cylindrical, wide at base, tapering towards apex, straight or slightly flexuous, smooth, light brown to dark brown, unbranched, 6–12 septate, 70–128 µm (x̄=100 µm, n=15) long, 7.5–12.5 μm (x̄=9 µm, n=15) wide. Conidiogenous cells holoblastic, monoblastic, integrated, terminal, determinate, cylindrical, smooth, mid to dark brown. Conidia acrogenous, solitary, dry, olivaceous brown to brown, pale at apex, obclavate, rostrate, smooth, straight or curved, truncate at base, 8–23– euseptate, sometimes with a mucilaginous sheath, 90–139 μm (x̄=113 µm, n=15) long, 9.5–16.5 µm (x̄=14 μm, n=15) wide.

Material examined – Thailand, Chiang Mai Province, saprobic on decaying wood at MRC, August 2020, Song Wang, SW280 (MFLU 21–0128, holotype)

GenBank numbers – OP077294 (LSU); ON980753 (SSU)

Notes – In the phylogenetic analyses our strain is closely realted with K. tectonae (Fig. 2). Kirschsteiniothelia spatiosum shares similar characteristics with Kirschsteiniothelia tectonae in having macronematous, unbranched, cylindrical, septate, conidiophores and solitary, obclavate, septate, conidia. However, K. spatiosum differs from K. tectonae in having a gelatinous rounded sheath at the apex of shorter and thinner conidia and in having shorter and thinner conidia (90–139×9.5–16.5 μm vs 135–150 × 16–19 μm). Kirschsteiniothelia spatiosum differs from K. tectonae in having shorter conidiophores (70–128 × 7.5–12.5 μm vs 200 × 4–8 μm).

Figure 1 –  Kirschsteiniothelia spatiosum (MFLU 21–0128, holotype) a–c Colonies on dead wood. d, e Conidiophore with conidia. f Conidiogenous cells and conidia. g Conidiophore. h–l Conidia. m Germinating conidium. Scale bars: a–c=100 μm, d–g=50 μm, m=100 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