Lentithecium yunnanensis W. H. Lu, Karun. & Tibpromma 2022, sp. nov.

Index Fungorum number: IF559622; Facesoffungi number: FoF 10778

Holotype: HKAS 123192

Etymology: Named after the place “ Yunnan ” where the new taxon was first discovered.

Saprobic on dead culms of Artemisia sp. in the marsh habitat. Sexual morph: Ascomata 190 – 220 μm diam, 220 – 240 μm high (x̅ = 201 × 228 μm, n = 6), scattered to gregarious, conspicuous at the surface, semi-immersed to immersed beneath host epidermis, sometimes sparse erumpent, subglobose to globose in section, with a short papillate ostiolar neck (40 – 70 μm long, 40 – 70 μm diam), central, black. Peridium 20 – 30 μm wide, thick-walled, multilayers, consist of dark – brown, thick - walled cells of textura angularis in the outermost layers, unequal thickness. Hamathecium 2 – 3 μm wide, hyaline, slenderly cylindrical, slightly septate, rarely anastomosing, unbranched, tubular psedoparaphyses. Asci 60 – 150 × 10 – 20 μm (x̅ = 82 × 14 μm, n = 25), 8 – spored, fissitunicate, clavate, bitunicate, oblong to cylindrical, the apex is broadly round with visible apical chambers, short - stalked with club shape perdicel. Ascospores 20 – 40 × 10 – 20 μm (x̅ = 29.7 × 7.5 μm, n = 30), overlapping, bi-seriate, hyaline, clavate to broadly fusiform with broadly rounded ends, slightly curved, 1 – 3-septate, slightly constricted at the middle septum, widest at the centre, tapering towards ends, smooth - walled, with large guttules, surrounded by a hyaline mucilaginous sheath (1 – 4 μm thick). Asexual morph: Undetermined.

Culture characteristics: Ascospores germinated on PDA within 20h, pure mycelia were transferred to PDA and cultured for two weeks at 25 °C, circular, effuse, irregular, flossy, velvety, pale brown to brown; reverse dark brown in the middle and yellow-white at the margin. Mycelium superficial and partially immersed raised. Hyphae septate branched, subhyaline, thin, smooth-walled. Incubated culture on PDA for eight months, but not get an asexual morph.

Material examined: China, Yunnan, Kunming, Songhua Dam Reservoir, on dead culms of Artemisia sp., Wenhua Lu, LL 96, 17 July 2021, (HKAS 123192, holotype), ex-type, KUNCC 22-10776 = KUNCC 22-10777.

Notes: Lentithecium yunnanensis was isolated on a dead culm of Artemisia sp. from Yunnan, China. Its morphology is comparable with the type species of Lentithecium and other taxa in Lentithecium (TABLE 3). The phylogenetic analyses of a combined sequence dataset (LSU, SSU, ITS, and tef 1 - α) position L. yunnanensis well separated from other taxa in Lentithecium with strong statistical supports (89% ML, 0.96PP, FIGURE 1). Lentithecium fluviatile is morphologically similar to our new species but differs from L. yunnanensis by having comparatively small ascomata (180 – 200 × 180 – 210 μm), at asci apex without an obvious apical chamber whereas L. yunnanensis has larger ascomata (190 – 218 × 222 – 236 μm) with a shallow ocular chamber on apex of bi-tunicate asci. Lentithecium fluviatile also has a relatively smaller (69 – 82 × 18 – 23 μm) asci compared with L. yunnanensis (58.4 – 154 × 11 – 18 μm), ascospore 24–31 × 7–10 μm, broadly fusiform, septate, hyaline, constricted at the septa, surrounded by a mucilaginous sheath (Ryckegem et al. 2001). In addition, L. clioninum differs from L. yunnanensis by having a relatively larger (210 – 280 × 330 – 430 μm) ascomata and (81.5–) 86–118 (–128) × 15–19 (–21) μm asci, ascospores of L. yunnanensis lack winglike sheaths as found in L. clioninum (Tanaka et al. 2015). Furthermore, the difference between L. yunnanensis and L. pseudoclioninum are mainly reflected in the following aspects, ascospores of L. yunnanensis hyaline, clavate to fusiform, 3-septums, clavate to multiple global guttules, smooth-walled, surrounded by hyaline mucilaginous sheath, with rounded ends; L. pseudoclioninum ascospore clavate to broadly fusiform, slightly curved, constricted at the septum. A synopsis of morphological characteristics of the accepted species of Lentithecium is provided in TABLE 3. Comparison of gene fragments of Lentithecium yunnanensis and four phylogenetically closely related species (TABLE 4). In addition, this is the first report of Lentithecium on the genus Artemisia in China.