Tarzetta tibetensis F.M. Yu, & Q. Zhao sp. nov.

Index Fungorum number: IF 900470; MycoBank number: MB 900470; Faceoffungi number: FoF 14239; Fig. 1

Etymology – Named after Tibet, China, where the type specimen was collected.

Saprobic on soil. Sexual morph: Apothecia up to ca. 10 mm broad, stipitate, cupuliform, scattered, hymenium light yellow, cream yellow, receptacle surface greyish yellow to greyish brown. Margin crenate and eroded, with brown tooth. Subhymenium and medullary excipulum thin, brown, cells of textura intricata, with hyaline hyphae, 2.5–5.0 μm wide. Ectal excipulum 6.5–29.5 μm diam., with cells of textura subglobulosa/angularis, hyaline to light brown, organized in small pyramidal brownish warts. Asci 215–320×11–17 μm, 8-spored, cylindrical, long narrowed to the base, croziers, operculate, inamyloid. Paraphyses 2.0–4.5 μm diam. wide, filiform, separate, branched, as long as asci, straight, hyaline, irregular at the top, digitate or with lateral bumps, the widest point at the apex 3.0–6.0 diam. Ascospores 14.5–21.5×8.5–11.5 μm (x=18.5×10.0 µm, n=50), ellipsoid, blunt rounded at both ends, uniseriate, hyaline, smooth, containing two or more small guttules that fuse into one at maturity. Asexual morph: Undetermined.

Material examined – China, Tibet, Shigatse City, Yadong Country, on soil, 2 July 2022, 27° 25′ 52.3487″ N, 88° 59′ 58.8944″ E, 3632 m a.s.l., F.M. Yu, FM22-109 (HKAS 127118, holotype), FM22-232 (HKAS 127117, paratype).

GenBank numbers – ITS: OQ422965, OQ417936, LSU: OQ418059, OQ418058.

Notes – The sequence data of our collections (HKAS 127117 and HKAS 127118) reveal species in Tarzetta as the closest matches with NCBI. Phylogenetic analyses of the combined ITS and LSU sequences (Fig. 2) showed that our collections formed a well-supported distinct subclade which is sister to the subclade comprising Tarzetta cupularis, T. catinus, T. cf. cupularis, T. melitensis, T. scotica, and T. spurcata. However, morphologically our collections are distinct from phylogenetically close species. There are four Tarzetta species viz. T. catinus, T. confusa, T. cupularis and T. linzhiensis have been reported in China. The apical ends of paraphyses in our collections are irregular with digitate or lateral bumps, which were distinctly different from other Tarzetta species collected in China. Therefore, we introduce our collections as Tarzetta tibetensis sp. nov.

Figure 2 – Phylogram generated from maximum likelihood analysis based on the combined ITS and LSU sequence data representing the species of Tarzetta and related taxa. Thirty-eight taxa were included in the combined locus alignment that comprised 1681 characters (LSU: 878, ITS: 803). The best scoring RAxML tree with a final likelihood value of−9181.759191 is presented. The matrix had 632 distinct alignment patterns, with 25.03% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.266168, C=0.225813, G=0.277987, T=0.230032; substitution rates: AC=1.673745, AG=2.397809, AT=1.502043, CG=1.309663, CT=4.583265, GT=1.0; gamma distribution shape parameter α=0.218698. Bootstrap support for ML equal to or greater than 75% and BI equal to or greater than 0.95 are given above the nodes. Geopyxis deceptiva (FH KH.04.61) and G. delectans (S-F274182) were used as the outgroup taxa. The newly generated sequence is indicated in blue bold. The ex-type strains are in bold