Three novel species and new records of Kirschsteiniothelia (Kirschsteiniotheliales) from northern Thailand Author de Farias, Antonio Roberto Gomes https://orcid.org/0000-0003-4768-1547 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand antonio.gom@mfu.ac.th Author Afshari, Naghmeh Department of Biology, Faculty of Sciences, Chiang Mai University, Chiang Mai 50200, Thailand & School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand Author Silva, Veenavee S. Hittanadurage https://orcid.org/0000-0001-8921-1370 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand Author Louangphan, Johnny Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand Author Karimi, Omid https://orcid.org/0000-0001-9652-2222 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand Author Boonmee, Saranyaphat https://orcid.org/0000-0001-5202-2955 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand text MycoKeys 2024 2024-02-02 101 347 370 http://dx.doi.org/10.3897/mycokeys.101.115286 journal article http://dx.doi.org/10.3897/mycokeys.101.115286 1314-4049-101-347 2D5BDC7B24EF5C5CB6939AAD2C5B0DB9 Kirschsteiniothelia inthanonensis J. Louangphan & Gomes de Farias sp. nov. Fig. 3 Etymology. The name refers to the location "Doi Inthanon" where the holotype was collected. Holotype. MFLU 23-0420 Description. Saprobic on decaying wood. Sexual morph : Not observed. Asexual morph : Hyphomycetes . Colonies on the host substrate are superficial, effuse, long hairy, fascicular, scattered, dark brown to black. Mycelium superficial and immersed, composed of branched, septate, pale brown and smooth hyphae. Conidiophores 611-1549 x 2.5-6.6 μm ( x̄ = 1070 x 4.1 μm , n = 20), macronematous, synnematous, compact fasciculate, straight to flexuous, brown to dark brown, branched at the apex, multi-septate, thick and smooth-walled. Conidiogenous cells 15-45 x 6.7-10.4 μm ( x̄ = 24.3 x 8 μm , n = 20), monotretic to polytretic, calyciform, integrated, discrete, terminal, darkened at the apex, proliferating portion, brown, 2-4 septate. Conidia 24-230 x 5.7-14.3 μm ( x̄ = 101 x 9 μm , n = 15), acrogenous, solitary, obclavate, rostrate, straight or curved, truncate at base, grey to brown, pale at apex, partly tapering towards and rounded at the apex, 2-10- euseptate, smooth-walled. Figure 3. Kirschsteiniothelia saprophytica (MFLU 23-0419, holotype) a host b, c appearance of ascomata on host surface d paraphyses e-g asci h-k ascospores l, m culture on PDA (front and reverse). Scale bars: 20 µm ( d-g ); 10 µm ( h-k ). Culture characteristics. Conidia germinated on PDA within 48 hours. Germ tubes germinated from end cell. Colony, reaching 30-35 mm diam. after one month at room temperature, circular form, flat, undulate edges, dense velvety surface, dark green on the surface, white mycelium on the tip, dark in reverse with dark green margin. Material examined. Thailand , Chiang Mai , Chom Thong , Doi Inthanon National Park , on twigs of Quercus oleoides , 30 November 2022 , Veenavee Silva, DIFWS5-01 (MFLU 23-0420, holotype ), ex-type living culture MFLUCC 23-0277 . Notes. Kirschsteiniothelia inthanonensis (MFLUCC 23-0277) resembles K. septemseptatum and K. nabanheensis in having septate, cylindrical conidiophores with branches near apex, integrated, terminal conidiogenous cells and solitary, obclavate, septate conidia without mucilaginous sheaths. However, K. inthanonensis MFLUCC 23-0277 has longer and smaller conidiophores than K. septemseptatum and K. nabanheensis (611-1549 μm vs. 250-580 μm and 320-588 μm ) and (2.5-6.6 μm vs. 6.5-14.5 μm and 8-12 µm ), respectively and elongated conidia ( Jayawardena et al. 2022 ; Liu et al. 2023 ). In addition, our phylogenetic analyses show that K. inthanonensis forms an independent branch with 100% MLBS and 1.00 BYPP support. BLASTn base pair comparisons between K. inthanonensis (MFLUCC 23-0277) and K. septemseptatum (MFLU 21-0126) show 95% similarity of ITS (479/504, 6 gaps), 99% similarity of LSU (844/853, no gaps) and 99% similarity of SSU (787/789, 2 gaps). Kirschsteiniothelia nabanheensis (HJAUP C2004) shows 94% similarity of ITS (483/513, 7 gaps), 99% similarity of LSU (540/547, no gaps) and 98% similarity of SSU (864/883, no gaps). Based on these data, we introduce K. inthanonensis as a new species.