Stictis anomianthi N.I. de Silva, Lumyong & K.D. Hyde, sp. nov.

Index Fungorum number: IF 900477; MycoBank number: MB 900477; Facesoffungi number: FoF 14187; Fig. 1

Saprobic on dead twigs of Anomianthus dulcis (Dunal) J.Sinclair. Sexual morph: Apothecia 250–350 μm high×600–700 μm diam. (x=270×650 μm, n=10), initially immersed, opening by entire pore at maturity, subglobose. Disc deeply cupulate, pale creamy, with white pruinose margin. Exciple comprising thin layer of hyaline, hyphal tissue, extending under the hymenium and with crystalliferous upper part. Hymenium 20–25 μm wide (x=22 μm, n=10), comprising hyaline cells of textura prismatica. Hamathecium comprising asci and paraphyses. Paraphyses hyaline, 1–2 µm wide (x=1.4 μm), numerous, long filiform, unbranched, aseptate. Asci 90–110×6–8 μm (x=100 × 7 μm, n=20), unitunicate, 8-spored, cylindrical, rounded apex with sessile or short pedicel. Ascospores 45–55×2–3 μm (x=49×2.4 μm, n=30), hyaline, fusiform, 6–8-septate, smooth, no gelatinous sheath observed, tapering towards the base. Asexual morph: Unknown.

Material examined – Thailand, Chiang Rai Province, on dead twigs attached to Anomianthus dulcis (Annonaceae), 4 April 2019, N.I. de Silva, AND8 (HKAS 107096, holotype).

GenBank numbers – LSU: OQ975316; ITS: OQ980248

Notes – A new species of Stictis is described as S. anomianthi and determined to be genetically distinct based onphylogenetic analyses of combined of LSU, ITS and mtSSU sequence data (Fig. 2). Phylogenetically, Stictis anomianthi (HKAS 107096) closely related to S. anhuiensis (HOU 1233a and HOU 1233M) with 94% ML support. Stictis anhuiensis was isolated from on fallen needles of Cunninghamia lanceolata (Cupressaceae) in Anhui Province, China (Li et al. 2016). However, S. anomianthi is clearly distinct from S. anhuiensis in having larger asci and ascospores. Stictis anomianthi has larger asci (90–110×6–8 μm) and 45–55×2–3 μm ascospores than S. anhuiensis has small asci (50–70×3.5–5 μm) and ascospores (32–50×1–1.5 μm) (Li et al. 2016). Stictis anhuiensis has aseptate ascospores and similarly, both S. pusilla and S. sarothamni have aseptate ascospores (Li et al. 2016). However, Stictis anomianthi has septate ascospores.

Figure 1 – Stictis anomianthi (HKAS 107096, holotype). a, b Appearance of ascomata on substrate. c, d Vertical section through an ascoma. e, f Vertical sections of peridium. g–i Paraphyses and asci. j, k Ascospores. Scale bars: a=500 μm, b=200 μm, c=100 μm, d=50 μm, e–i=20 μm, j, k=10 μm

Figure 2 – Phylogram generated from the maximum likelihood analysis based on combined LSU, ITS and mtSSU sequence data representing selected genera of Stictidaceae. Related sequences are taken from Thiyagaraja et al. (2021). Diploschistes scruposus (SFB 95) and Myriotrema olivaceum (Kalb 39107) are used as the outgroup taxa. Forty-seven strains are included in the combined gene analyses comprising 3,380 characters after alignment (LSU=930, ITS=560, mtSSU=700). The best RAxML tree with a final likelihood value of − 22,586.790930 is presented. The matrix had 1503 distinct alignment patterns, with 47.53% undetermined characters or gaps. Estimated base frequencies were as follows: A=0.241216, C=0.242934, G=0.273292, T=0.242558; substitution rates AC=1.074003, AG=2.167182, AT=1.275282, CG=0.844529, CT=5.569289, GT=1.0; gamma distribution shape parameter α=0.509718. Bootstrap values for maximum likelihood equal to or greater than 75% and Bayesian posterior probabilities equal to or greater than 0.95 are given above the nodes. New strain is indicated in blue bold