Oxydothis yunnanensis Q.R. Li & J.C. Kang, sp. nov.

Index Fungorum number: IF; MycoBank number: MB;Facesoffungi number: FoF 05080; Fig. 1

Etymology – based on the collected location, Yunnan Province, China.

Saprobic on branches of palms. Sexual morph: Ascomata 223–363 μm diam., 74–85 μm high, forms slightly raised blistering areas on the host surface, clustered, immersed, subglobose, ostiole, coriaceous, black, eccentric, long axis horizontal to that of the host surface with neck at one end long axis parallel to plant surface. Peridium 28–40 μm thick, comprised of 2–3 layers outer layers of oblong, compressed, dark-brown cells of textura angularis. Asci 108–152×6.5–13.5 μm (x=132×8.5 μm, n=30), 8-spored, unitunicate, cylindrical, mostly bending, short pedicellate, apically rounded, with a J- subapical ring not blue in Melzer’s reagent. Ascospores 54–69×2.5–4 μm (x=59.5 × 3.5 μm, n=30), filiform, 2-seriate, uniseptate at the center, hyaline, tapering from center to end. Asexual morph: Undetermined.

Culture characters – The colony on PDA medium with a diameter of 5 cm after two weeks at 25 °C; white, circular, surface rough. Not sporulate on OA or PDA.

Material examined – China, Yunnan Province, Kunming City, Kunming Botanical Garden, on dead culms of palm, 15 August 2015, Q.R. Li, KIB 8 (GZUH 0127, holotype), ex-type culture GZUCC 0127.

GenBank numbers – ITS: ON176681, LSU: ON176684

Notes – ITS and LSU sequences of our collection (GZUH 0127) reveals Oxydothis species as the closest matches with NCBI and phylogenetically, it is related to Oxydothis inaequalis Hidayat, To-anun & K.D. Hyde with ML/BI = 100%/0.99 statistical support (Fig. 2). However, base pair differences of our collection (GZUH 0127) with Oxydothis inaequalis are 15.5% for ITS and 3% for LSU. Our collection (GZUH 0127) is morphologically similar to O. livistonae Syd. & P. Syd., O. nonamyloidea K. D. Hyde and O. rhapidicola Konta & K.D. Hyde. in the shape of its ascospores (Fröhlich and Hyde 1994; Hidayat et al. 2006; Konta et al. 2016). However, O. nonamyloidea and O. livistonae have larger ascospores than our collection viz. 94‒115×3.5‒4.5 μm and 150‒170×4‒5.5 μm respectively. Oxydothis rhapidicola differs from our collection by its smaller ascospores (47‒50×3‒5 μm) and the slit-like J+ascus subapical ring. Nevertheless, O. yunnanensis differs from O. inaequalis by its smaller ascospores (60×3.5 μm vs. 78–100×5–6 µm) and the J- ascus subapical ring. Therefore, we introduce our collection as a new species, Oxydothis yunnanensis.

Figure 1 – Oxydothis yunnanensis (GZUH 0127, holotype). a Examined material. b, c Ascomata on the surface of host. d Cross-section of ascomata. e Peridium. f, g Ascus apex with a J- subapical ring (stained in Melzer’s reagent). h–k Asci. l–n Ascospores. Scale bars: b, c=500 μm, d=50 μm, e–g=5 μm, h–n=10 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined ITS, LSU, and tef1-α sequence data of 23 taxa, which comprised 2549 characters (ITS=697, LSU=866, tef1-α=984). The best scoring RAxML tree with a final likelihood value of − 9941.739756 is presented. The matrix had 752 distinct alignment patterns, with 36.07% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.234608, C=0.258487, G=0.267824, T=0.239080; substitution rates: AC=0.999075, AG=1.873946, AT=1.369435, CG=1.130755, CT=4.743944, GT=1.0; gamma distribution shape parameter α=0.272581. Bootstrap support for maximum likelihood (ML) equal to or greater than 50% and clade credibility values greater than 0.90 (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 blue bold. The tree is rooted to Vialaea minutella (BRIP 56959) and V. mangiferae (MFLUCC 12-0808)