Oxydothis dehongensis G.Q. Zhang, D.Q. Dai & L.S. Han, in Cao et al., Fungal Diversity 132: 461 (2025)

Index Fungorum number: IF 901554; MycoBank number: MB 901554; Facesoffungi number: FoF 15291; Figs. 1, 2

Etymology – refers to Dehong prefecture, the locality of the type specimen.

Holotype – MHZU 23–0267.

Sexual morph: Ascomata 550–850 µm diam., 340–550 µm high, forming slightly raised domes, solitary or clustered in groups (mostly 2–3), immersed, subglobosa, truncated at the base, conical in section, coriaceous, papilla at one end curving upwards to the host surface. Peridium 15–20 µm wide, composed of 2–3 layers of pale brown to hyaline cells with textura prismatica. Paraphyses seems to dissolve during maturation. Asci 190–250 µm × 13–20 µm (x̄ = 232 × 16 µm, n = 20), 8-spored, cylindrical, straight to curve, pedicellate, unitunicate, with a wedge-shaped, J + , apical ring, 2–4 µm diam, bluing in Melzer’s reagent, truncated at the top. Ascospores 45–95 × 4.5–9 µm (x̄ = 72 × 6.5 µm, n = 30), fusiform, initially hyaline, becoming brown when overmatured, obliquely 1-seriate, tapering gradually from a constricted central or seldom upper central septum to short, pointed processes, smooth walled, guttulate, pointed at ends. Asexual morph: undetermined.

Material examined – CHINA, Yunnan Province, Dehong Dai and Jingpo autonomous prefecture, Mang city, Xuangang village, 24°45’N 98°43’E, 919.77 m, 22 Jul 2023, Gui-Qing Zhang, Dong-Qin Dai, Li-Su Han, HLS67 (MHZU 23–0267, holotype), ex-type ZHKUCC 23–0986, culture ZHKUCC 23–0987; Ibid. HLS58 (MHZU 23–0269), culture ZHKUCC 23–0988.

GenBank – ZHKUCC 23–0986: PP580831 (ITS), PP002130 (nucLSU), PP002127 (nucSSU), PP001172 (tef1); ZHKUCC 23–0987: PP580832 (ITS), PP002131 (nucLSU), PP002128 (nucSSU), PP001173 (tef1); ZHKUCC 23–0988: PP598863 (ITS), PP002132 (nucLSU), PP002129 (nucSSU), PP001174 (tef1).

Notes – Combined ITS, LSU and tef1 gene analysis (Fig. 2) showed that our isolate (ZHKUCC 23–0986, ZHKUCC 23–0987, ZHKUCC 23–0988) grouped with Oxydothis inaequalis, Oxydothis yunnanensis and O. fortunei, forming a distinct clade with ML/BP = 100%/1 statistical support. Our collection differs from Oxydothis inaequalis by it has larger asci and ascospores while O. inaequalis with narrower (11.25–13.75 µm) asci and narrower (5–6.25 µm) ascospores (Hidayat et al. 2006). Our collection differs from Oxydothis fortunei by its wide asci with J + , apical ring and O. fortunei has small, solitary or aggregated ascomata (200–315 µm diam.), smaller-sized asci (9–14 µm), J- sub apical ring and smaller ascospores (56–72 µm) (Hu et al. 2022a). Our collection differs from Oxydothis yunnanensis in having wide asci with J + , apical ring, 1-seriate, large sized asci and ascospores while Oxydothis yunnanensis with 2-seriate, smaller-sized asci (108–152 × 6.5–13.5 µm) and ascospores (54–69 × 2.5–4 µm) (Senanayake et al. 2023). Our collection does not fit with any exist species and thus, we introduce our collection as a new species, Oxydothis dehongensis.

Figure 1 – Oxydothis dehongensis (MHZU 23–0267, holotype). a Bamboo specimen. b Appearance of fruiting bodies on host substrate. c Section of ascoma. d Peridium. e–h Asci in water. i Reaction of apical ring in Melzer’s reagent. j–n Ascospores. o Germinating ascospores. p, q Cultures on PDA from above and below. Scale bars: b = 500 µm, c = 1000 µm, d = 50 µm, e–i = 50 µm, j–o = 20 µm.

Figure 2 – Phylogram generated from Maximum Likelihood analysis based on combined ITS, LSU and tef1 sequence data of 24 taxa. Bootstrap support for ML equal to or greater than 50% and clade credibility values greater than 0.95 (the rounding of values to 2 decimal proportions) from Bayesian inference analysis are labelled at each node. Ex-type strains are in bold, while the new isolate is indicated in red bold. The tree is rooted to Vialaea minutella (BRIP 56959) and V. mangiferae (MFLUCC 12–0808).