Nigropunctata conspicua N. Wu & Jian K. Liu [as ‘conspicosa‘], in Cao et al., Fungal Diversity 132: 501 (2025)

Index Fungorum number: IF 664963; MycoBank number: MB 664963; Facesoffungi number: FoF 15930; Figs. 1, 2

Etymology – The specific epithet reflects the conspicuous sheath of ascospores.

Holotype – MFLU 24–0128.

Saprobic on dead branches of bamboo. Sexual morph: Ascomata deeply immersed throughout the host tissue, solitary, visible as black domes on the substrate, vertical sections subglobose or conical, ostioles centric. Peridium easily detached from substratum when dry, composed of two strata, outer stratum thick, consisting dark brown to hyaline cells of textura angularius, inner stratum thin. Paraphyses 2–5 µm (x̄ = 3 µm, n = 10), wide, hyaline, branched, longer than the asci, septate, slightly constricted, guttulate, embedded in a gelatinous matrix, smooth-walled. Asci 126–145 × 10–11 µm (x̄ = 136 × 10 µm, n = 20), 8-spored, unitunicate, cylindrical, short-pedicellate or sometimes apedicellate, apically rounded. Ascospores 14–19 × 7–8 µm (x̄ = 17 × 7 µm, n = 30), oblong to broadly ellipsoidal, hyaline, mostly aseptate, sometimes 1-septate, slightly con stricted at the septum when young, becoming dark brown at maturity, aseptate, guttulate, with or without a slightly curved germ slit running along with the entire ascospore length, surrounded by a 5–12 µm (x̄ = 8 µm, n = 30) thick mucilaginous sheath, slightly constricted at center. Asexual morph: Undetermined.

Culture characteristics – Ascospores germinated on PDA within 12 h at 25 °C. Colonies on PDA reached 5 cm diam. after 2 weeks at 20–25 °C, mycelium white, medium sparse, circular, flat, white to yellowish at the center.

Material examined – THAILAND, Chiang Rai Province, Amphoe Mae Sai, Tambon Wiang Phang Kham, Paholyothin Road, 20°24’16.6”N 99°52’42.4”E, on dead branches of bamboo (Poaceae), 4 July 2019, Na Wu, YW87 (MFLU 24–0128, holotype; MFLUCC 24–0092, ex-type) and YW88.

GenBank – MFLU 24–0128: PP868305 (ITS), PP868306 (nucLSU), PP869337 (rpb2), PP869336 (tef1).

Notes – Multi-gene phylogenetic analyses showed that Ni. conspicosa (MFLUCC 24–0092) constitute a distinct lineage in Nigropunctata but claded closer to Ni. khalidii and Ni. thailandica (Fig. 1). Nigropunctata conspicosa can be distinguished from the above closely related species based on ITS, LSU and tef loci for Ni. khalidii (18/434 bp in ITS) and Ni. thailandica (30/582 bp in ITS, 23/947 bp in LSU, 31/935 bp in tef1). Morphologically, Ni. conspicosa is similar to Ni. khalidii and Ni. thailandica, which in having deeply immersed ascomata with two-layered peridium comprising cells of textura angularis, wide paraphyses and unitunicate, cylindrical asci with a short pedicel and hyaline to dark brown ascospores, covered with a mucilaginous sheath. However, Ni. Conspicosa differs from Ni. khalidii and Ni. thailandica by its shorter asci and ascospores with thicker mucilaginous sheath, and no germ slit was observed in Ni. khalidii.

Figure 1 – Phylogenetic tree generated from the Maximum Likelihood analysis based on the combined ITS, LSU, rpb2 and tef sequence data of Pallidoperidiaceae. The ML (= 50%) and BI (= 95%) bootstrap supports are given near the nodes, respectively. New species are shown in red. “T” refers to a type specimen. The tree is rooted with, Neogyrothrix oleae (CPC 37063, CPC 37069).

Figure 2 – Nigropunctata conspicosa (MFLU 24–0128, holotype). a Substrate. b, d Sections through ascomata. c ascomata in dead substrate. e–g Asci. h Paraphyses. i–m Ascospores (m in Indian ink showing the sheath). n Germinated ascospore. o–p Colonies on PDA, o from above, p from below. Scale bars: b = 100 µm, c = 10 µm, d–h = 20 µm, i–n = 5 µm.