Index Fungorum Number: IF559726; Facesoffungi number: FoF11796

Etymology:—The specific epithet “ thailandica ” refer to the country in which the fungus was first collected

Holotype:— MFLU 19-2771

Epiphytic on the upper surface of dead leaves of Dimocarpus longan Lour. (Sapindaceae), visible as small black dots. Superficial hyphae absent. Sexual morph: Thyriothecia 200–260 × 210–280 μm (x = 230 × 240 µm, n = 10), solitary, superficial, scattered, flattened, circular, brown to black, easily be removed from the substrate, poorly developed basal layer, with prominent, darker, central ostiole, darker around the ostiole, dark brown towards the outer lighter rim, irregularly rounded at the margin. Upper wall containing brown cells of textura angularis, radiating in slightly irregular, parallel lines from center to the outer rim. Hamathecium containing 2 μm wide, branched pseudoparaphyses. Asci 40–46 × 5–7 μm (x = 45 × 6 µm, n = 20), 8-spored, fissitunicate, bitunicate, short pedicellate, cylindrical to cylindric-clavate, apically rounded, with an ocular chamber. Ascospores 9–11 × 3–4 μm (x = 10.5 × 3.5 µm, n = 10), 1–2-seriate, hyaline, fusiform, rounded ends, 1-septate, constricted at the septum, apical cell swollen and wider, basal cell sub-conical, guttulate, two appendages in upper cell, smooth-walled. Asexual morph: Undetermined.

Culture characteristics:— Colonies on PDA, 18–22 mm diam. after 4 weeks at 25 °C, colonies from above: medium dense, circular, raised, surface smooth, entire margin, light green at margin, dark grey to brown at centre; reverse: light brown to light green at margin, dark grey to black at centre. Mycelium dark grey to black with tufting.

Material examined:— Thailand, Chiang Mai, dead leaves of Dimocarpus longan (Sapindaceae), 25 April 2018, D.S. Tennakoon, DHAY021A (MFLU 19-2771, holotype); ex-type living culture, SDBR-CMU438. ibid. 28 April 2018, DHAY021B (NCYU 19-0090, paratype); ex-paratype living culture, SDBR-CMU439.

GenBank numbers:—MFLU 19-2771: LSU: ON751750; ITS: ON751739; NCYU 19-0090: LSU: ON751751; ITS: ON751740.

Notes:—The morphological characteristics of our collection (MFLU 19-2771 and NCYU 19-0090) tally well with the generic concept of Tumidispora, by having flattened, circular, brown to black thyriothecia, cylindrical to cylindricclavate, short pedicellate asci and 1-septate, hyaline ascospores with a swollen apical cell (Ariyawansa et al. 2015). But our collection can be distinguished from the type (T. shoreae) in having shorter asci (40–46 × 5–7 μm vs 53–55 × 7–8 μm) and ascospores (9–11 × 3–4 μm vs 14–15 × 4–5 μm). In addition, our collection ascospores are distinctly fusiform with rounded ends and consist of two appendages in the upper cell, whereas T. shoreae has narrowly fusiform ascospores with sub-papillate ends and lacking appendages (Ariyawansa et al. 2015). Phylogeny results show that our collection (MFLU 19-2771 and NCYU 19-0090) forms an independent lineage sister to T. shoreae isolates (MFLUCC 12-0409 and MFLUCC 14-0574) with strong statistical support (100% ML, 100% MP, 1.00 BYPP, FIGURE 1). Thus, we introduce our collection (MFLU 19-2771 and NCYU 19-0090) as a new species, T. thailandica from the dead leaves of Dimocarpus longan in Thailand.