A new addition to Kirschsteiniotheliaceae: Kirschsteiniothelia chiangmaiensis sp. nov. from Northern Thailand Author Louangphan, Johnny 0000-0003-3845-6145 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand. & School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand. johnnyy7890@gmail.com Author Perera, Rekhani H. 0000-0002-1360-5362 School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea. hansi.rekha2@gmail.com Author Gomes De Farias, Antonio R. 0000-0003-4768-1547 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand. rfariasagro@gmail.com text Phytotaxa 2024 2024-01-11 634 1 49 62 http://dx.doi.org/10.11646/phytotaxa.634.1.4 journal article 10.11646/phytotaxa.634.1.4 1179-3163 13878822 Kirschsteiniothelia chiangmaiensis J. Louangphan, AR. Gomes de Farias & R.H. Perera , sp. nov. Index Fungorum number: IF901120, Facesoffungi number: FoF 14883 Etymology: The name refers to Chiang Mai Province , where the holotype was collected. Holotype : MFLU 23–0358 Saprobic on decaying wood. Sexual morph: Ascomata 133–247 μm high, 150–307 μm diam. (x̄ = 180.7 × 232.4 µm, n = 6), scattered, immersed to semi-immerse, black, sub-globose or hemispherical to broadly conical with the base flattened, apex plane or papillate, rounded to truncate, sometimes split. Ostiole 40–70 µm wide with short papilliform, Peridium 25–70 µm thick on sides but thin and pale, immersed in host tissue at the base, comprising several layers of textura angularis with pale brown inner layer cells and dark brown to black outer layer cells. Hamathecium composed of dense filiform pseudoparaphyses, 1.5–2.6 µm wide, branched, septate, hyaline, embedded in a gelatinous matrix. Asci 76–119 × 24–30 µm (x̄ = 93.8 × 27.2 µm, n = 13), bitunicate, 8-spored, cylindrical-clavate with a short stalk up to 5 µm long, straight or slightly curved, apically rounded, with a small ocular chamber. Ascospores 20–31 × 9–12 µm (x̄ = 25.6 × 10.7 µm, n = 45), bi- or tri-seriate in the middle and uniseriate in the top of the ascus, ellipsoid to fusiform, narrowly to broadly ellipsoidal with rounded or slightly pointed at the ends, 1-septate, septum submedian and deeply constricted, the upper cell distinctly larger than the lower cell, each cell containing a distinct large guttule and densely pluri-guttulate, brown, thick-, smooth-walled, with a mucilaginous sheath. Asexual morph: Undetermined. Culture characteristics : Ascospores germinating on PDA within 24–48 hours. Colonies growing on PDA dense, reaching 1 cm diam. after a week at room temperature and 3–4 cm diam. within a month. In the first week, the surface was covered with a pale white mat of aerial hyphae, then became greyish-green and dark green, composed of brown to dark brown, reverse at the first dark green with a white margin, then dark brown to black. Specimens examined : THAILAND , Chiang Mai Province , MaeTaeng District, Pha Deng Village, Mushroom Research Center (MRC), on decaying wood in a forest spot, 10 December 2022 , Johnny Louangphan, MC4.1 (MFLU 23–0358, holotype ), ex-type living culture MFLUCC 23–0209. Notes —The phylogenetic analyses revealed that K. chiangmaiensis formed an independent lineage, sister to K. puerensis (ZHKUCC 22-0271 and ZHKUCC 22-0272), but with low bootstrap support 68% ML/0.76 BYPP (<75% ML and 0.95 BYPP) ( Figure 1 ). The comparison of the base pairs between K. chiangmaiensis and the three closely related species is shown in Table 3 . Kirschsteiniothelia chiangmaiensis is reported from its sexual morph, while K. puerensis , K. thailandica , and K. xishuangbannaensis , are reported from their asexual morphs ( Hyde et al. 2023 , Sun et al. 2021 , Xu et al. 2023 ). Therefore, we could not compare the morphology between the above species. When considering the sexual morph, K. chiangmaiensis is morphologically similar to K. aethiops (= K. atra ), the type species and K. thujina from their ascospore shape and septation. However, K. chiangmaiensis differs primarily from K. aethiops by smaller immerged ascomata (150–307 μm vs 300–600 μm diam.), wider asci (24–30 µm vs 12–15 μm), pluri-guttulate ascospores, and deviates from K. thujina by smaller ascomata (150–307 μm vs 300–500 μm diam.), smaller ascospore (20–31 × 9–12 µm vs 36–50 × 15–17 μm), and mucilaginous sheath in ascospores ( Table 4 ), confirming the taxonomic placement within the Kirschsteiniothelia . Thus, we introduce K. chiangmaiensis as a new species based on morphology and phylogeny. TABLE 3. Base pair differences of ITS, LSU, and SSU gene loci of Kirschsteiniothelia chiangmaiensis and closely related species.

K. chiangmaiensis
Species
ITS	LSU	SSU
K. puerensis	7.11% (33/464 bp), 13 gaps	3.70% (32/863 bp), 3 gaps	2.09% (22/1051 bp), 4 gaps
K. thailandica	8.63% (43/498 bp), 19 gaps	3.22% (26/806 bp), no gaps	1.16% (12/1033 bp), 1 gap
K. xishuangbannaensis	9.39% (42/447 bp), 12 gaps	1.96% (16/815 bp), 4 gaps	1.13% (12/1055 bp), 3 gaps

FIGURE 2 . Kirschsteiniothelia chiangmaiensis on decaying wood (MFLU 23–0358, holotype). A. Host b. The appearance of ascomata on the host surface. c–e. Vertical section through an ascoma. f, g Structure of peridium. h. Ostiole. i. Pseudoparaphyses. j–m.Asci. n. Small ocular chamber at the apical inner layer of the ascus. o–r. Ascospores. s. Ascospore showing sheath in India ink. t. Germinating ascospore. u. Colony growing on PDA for 30 days (both upper and lower sides). Scale bars: b = 200 μm, c = 100 μm, d, e = 50 μm, f, h–m = 20 μm, g, n–t = 10 μm. TABLE 4. Synopsis of morphological characteristics of K. chiangmaiensis closely related species and the Kirschsteiniothelia sexual taxa reported from Thailand. Unavailable data are shown as “–”.

Species	Host	Country	Ascomata	Ostiole	Peridium	Pseudoparaphyses	Asci	Ascospores	References
K. aethiops (= K. atra )	Carpinus / dead wood/ querus / submerged wood	Belgium/ China/ Germany/ U.S.A	300–600 μm diam., scattered, arising singly or in small groups, colonies not delimited, hemispherical to subglobose	20–30 μm diam., short papilliform or plane	40–60 μm thick, dark brown, thick- walled, textura angularis	2.5–3.5 μm thick, cellular, persistent, abundant, regularly septate, branched	70–90 × 12–15 μm, broadly subcylindricall, short-stalked, bitunicate, 4 or 8- spores	25–33 × 8.5–12.0 μm, ellipsoid, rounded or somewhat constricted at the apices, 1-septate, the upper cell usually larger in size, somewhat septum constricted, brown, almost smooth	Hawksworth (1985)
K. chiangmaiensis	Undetermined decaying wood	Thailand	133–247 × 150–307 μm, scattered, immersed to semi- immerged, sub-globose or hemispherical, black	Short papilliform 40–70 µm wide	25–70 µm thick- walled, pale brown -black textura angularis	Branched, 1.5–2.6 mm wide, hyaline, embedded in a gelatinous matrix	76–119 × 24–30 µm, 8-spored, cylindrical- clavate with a short stalked, straight or slightly curved	20–31 × 9–12 µm, ellipsoid to fusiform, rounded or slightly pointed at the end, 1-septate, deeply constricted, the upper cell larger, guttulate, brown, smooth-walled, with sheath	This study
K. emarceis	Deadwood	Thailand	109–280 × 101–318 µm, clustered, solitary or scattered, superficial, slightly immersed, subglobose to globose, dark brown to black, central ostiole	–	12– 40 µm thick, composed of 3–4 layers of textura angularis, inner layer cells pale brown, outer layer black	Hyaline, 1–2 µm wide, embedded in a gelatinous matrix,	88–140 × 18–24 µm, 8-spores, bitunicate, fissitunicate, cylindrical to clavate, apically rounded	25–28 × 8–9 µm, ellipsoidal, slightly curved, biseriate, septum median to supra-median, dull green, becoming brown to dark brown, one-septate, two-celled, smooth walled, lack mucilaginous sheath	Boonmee et al. (2012)

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