Kirschsteiniothelia weiningensis X. J. Xiao, Y. Z. Lu & K. D. Hyde 2025, sp. nov.

Kirschsteiniothelia weiningensis X. J. Xiao, Y. Z. Lu & K. D. Hyde sp. nov. Fig. 5 Etymology. Referring to the collecting location at Weining District in China. Holotype. HKAS 132143. Description. Saprobic on decaying wood in a freshwater habitat. Sexual morph: Undetermined. Asexual morph: Colonies on natural substrate effuse, dark brown to black, hairy. Mycelium immersed, composed of brown to dark brown, branched, septate, smooth hyphae. Conidiophores 75–125 × 5–10 μm (x ̄ = 97 × 7 µm, n = 20), macronematous, mononematous, erect, straight to slightly curved, unbranched, cylindrical, brown to dark brown, multi-septate, thick-walled. Conidiogenous cells 10–25 × 5–8 µm (x ̄ = 15 × 6 μm, n = 20), holoblastic, monoblastic, integrated, terminal, cylindrical, mid to dark brown, percurrently proliferating. Conidia 20–45 × 6–10 µm (x ̄ = 37 × 8 μm, n = 20), acrogenous, solitary, dry, pale brown to brown, obclavate, rostrate, straight or slightly curved, truncate at base, septate, slightly constricted at the septa, with a gelatinous sheath at apex. Cultural characteristics. Conidia germinating on PDA medium within 24 h and germ tube produced from the truncate base. Colonies on PDA medium reaching to 21 mm diam in 24 days at 28 ° C in natural light, circular, dense, mycelium slightly aerial, with raised center and rounded edge, grayish green to dark green from above and below. Material examined. China • Guizhou Province, Weining County, Wujiangyuan river, 26 ° 52 ' 33 " N, 104 ° 22 ' 18 " E, on decaying wood in a freshwater habitat, 2 August 2023, Xingjuan Xiao, WJY 23 (HKAS 132143, holotype), ex-type living strain GZCC 24-0072. Notes. Phylogenetically, Kirschsteiniothelia weiningensis (GZCC 24-0072) grouped with K. cangshanensis (MFLUCC 16-1350) and Kirschsteiniothelia sp. (KUNCC 23-13756 and KUNCC 23-14559), but in a distinct lineage (Fig. 1). Kirschsteiniothelia weiningensis and K. cangshanensis are both sporidesmium-like taxa and share highly similar characteristics, which render their differentiation based solely on morphology a challenge. This is a common occurrence among many sporidesmium-like taxa (Su et al. 2016). Nevertheless, ITS comparison reveals that K. weiningensis (GZCC 24-0072) exhibits 92 % identity (684 / 740, 14 gaps) and 93 % identity (474 / 502, 2 gaps) to K. cangshanensis (MFLUCC 16-1350) and Kirschsteiniothelia sp. (KUNCC 23-13756), respectively. Therefore, we propose K. weiningensis as a new species.