Kirschsteiniothelia longirostrata X. Tang, K. D. Hyde, Jayaward. & J. C. Kang 2024, sp. nov.

Kirschsteiniothelia longirostrata X. Tang, K. D. Hyde, Jayaward. & J. C. Kang, sp. nov. Fig. 6 Etymology. The specific epithet ‘ longirostrata ’ refers to the conidia containing a long rostrate. Holotype. GZAAS 23-0809. Description. Saprobic on an unidentified submerged decaying wood. Sexual morph: Undetermined. Asexual morph: Colonies on the natural substrate superficial, effuse, gregarious, hairy, black, glistening. Mycelium partly immersed on the substrate, composed of branched, septate, smooth-walled hyphae, pale to dark brown. Conidiophores 80–252 × 4.5–9.5 μm (x ̄ = 161.3 × 6.8 μm, n = 20), macronematous, mononematous, solitary, cylindrical, straight, or slightly flexuous, unbranched, percurrent, smooth, guttulate, 4–13 - septate, sometimes slightly constricted at the septa, brown to dark brown tapering towards the apex and wider at the base. Conidiogenous cells 6.5–16 × 5–9 μm (x ̄ = 13 × 7 μm, n = 20), monoblastic, terminal or indeterminate, percurrently proliferating, cylindrical, pale brown to brown. Conidia 36.5–109 (– 160) × 8–16 μm (x ̄ = 71 × 12 μm, n = 30), solitary, acrogenous, cylindrical, obpyriform to obclavate, rostrate 15–100 (– 120) × 2.5–6 μm (x ̄ = 48 × 4.3 μm, n = 30), smooth, straight or curved, guttulate, 6–18 - septate, slightly constricted and darker at the septa, proliferating, pale brown to brown, becoming paler towards the apex, with a truncate base and a mucilaginous sheath surrounding the upper part of the apex. Culture characteristics. Conidia germinating on PDA within 24 hours, producing germ tubes from the apex. Colonies displayed a circular morphology with dense, flat, spreading and fluffy growth, with an entire margin. The surface exhibited an olivaceous-green hue with a darker edge, while the reverse colonies displayed a circular shape with an entire margin, appearing blackish-green. Material examined. China • Hainan Province, Jianfengling National Forest Park, saprobic on submerged unidentified decaying wood, 23 August 2021, Zili Li, T 10 (GZAAS 23-0809, holotype) ex-type living culture GZCC 23-0733. Notes. Kirschsteiniothelia longirostrata exhibits sporidesmium-like characteristics and shares similar features with other Kirschsteiniothelia species. Kirschsteiniothelia longirostrata can be distinguished from other Kirschsteiniothelia species in having different sizes and shapes of conidiophores, conidiogenous cells and unique features of conidia, such as obpyriform to obclavate, long rostrate, proliferating, with a mucilaginous sheath surrounding the upper part of the apex. Unlike K. crustacea, K. longirostrata has cylindrical, proliferating conidiogenous cells and obpyriform to obclavate conidia, with longer (15–100 (– 120) × 2.5–6 μm), guttulate, proliferating rostrate structures and a mucilaginous sheath surrounding the upper part of the apex. Molecular data further supports the establishment of Kirschsteiniothelia longirostrata as a novel taxon. Based on our phylogenetic analyses, K. longirostrata is sister to K. crustacea (MFLU 21-0129) with 94 % ML and 1.00 PP support (Fig. 1). The comparison of the nucleotides between the sequences of K. longirostrata (GZCC 23-0733) and K. crustacea (MFLU 21-0129) shows differences of 8.4 % (39 / 467 bp) across ITS and 0.7 % (5 / 718 bp) across LSU, excluding gaps. However, we were unable to compare the nucleotide differences across SSU as K. crustacea lacks sequence data for this locus. Based on these findings, we introduce Kirschsteiniothelia longirostrata as a novel species, following guidelines outlined in Jeewon and Hyde (2016) and Maharachchikumbura et al. (2021).