Tarzetta urceolata L. Lei, & Q. Zhao sp. nov.

Index Fungorum number: IF 900471; MycoBank number: MB 900471; Faceoffungi number: FoF 14240; Fig. 1

Etymology – The epithet refers to its urceolate apothecia.

Saprobic on a humus layer covered with moss. Sexual morph: Apothecia ca. 20 mm broad, stipitate, urceolate, scattered, hymenium greyish brown when fresh, receptacle surface whitish, yellowish grey to olive grey, with finely white-powdery. Margin involute when mature. Subhymenium and medullary excipulum 287–345 μm, well developed, cells of textura intricata, with hyaline hyphae 2.5–8.5 μm wide. Ectal excipulum ca. 300 μm, cells of
textura subglobulosa/angularis, with 7–26 μm wide, hyaline to brown, organized in small pyramidal brownish warts. Asci 400–437×13–17.5 μm, 8-spored, cylindrical, long narrowed to the base, croziers, operculate, inamyloid. Paraphyses 2.5–4.5 μm wide, filiform, separate, branched, as long as asci, apex enlarged or constrictive slightly, straight or curved at the apex. Ascospores 8.5–13.5 × 6.5–9 μm ( =11.5 × 8.0 µm, n=50), subglobose, broad ellipsoid to ellipsoid, hyaline, smooth. Asexual morph: Undetermined.

Material examined – China, Tibet, Nyingchi County, Chayu City, on ground covered with moss, 15 July 2022, 28° 36′ 35.0415″ N, 98° 5′ 22.2463″ E, 4107 m a.s.l., F.M. Yu, FM22-244 (HKAS 127116, holotype).

GenBank numbers – ITS: OQ422966, LSU: OQ418060.

Notes – Our collection (HKAS 127116) clustered with Tarzetta linzhiensis with ML/BI=100%/1.00 statistical support (Fig. 2) in combined ITS and LSU gene analyses. The nucleotide comparison of sequences of our collection and T. linzhiensis reveals 9.33% in ITS and 1.55% in LSU. Morphologically, our collection differs from T. linzhiensis by its longer asci (400–437 μm vs. 310–385 μm), and smaller (8.5–13.5×6.5–9 μm vs 18.5–22.5×10–13.5 μm) ascospores.

Figure 1 – Tarzetta urceolata (HKAS 127116, holotype). a Typical mature specimens. b Anatomic structure of a portion of an apothecium. c Hymenium. d Subhymenium, medullary excipulum, and ectal excipulum. e Asci and paraphyses. f Asci. g Paraphyses. h Upper part of paraphyses. i Ascospores. Scale bars: a=2.5 cm, b–d=200 μm, f=100 μm, g, h=50 μm, i=20 μm

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