Tatraea yuxiensis C.J.Y. Li & Q. Zhao, 2024

Li, Cui-Jin-Yi, Thilini Chethana, Kandawatte Wedaralalage, Eungwanichayapant, Prapassorn Damrongkool, Zhou, De-Qun & Zhao, Qi, 2024, Additional four species of Tatraea (Leotiomycetes, Helotiales) in Yunnan Province, China, MycoKeys 102, pp. 127-154 : 127

Tatraea yuxiensis C.J.Y. Li & Q. Zhao sp. nov.

Fig. 8

Etymology.

The specific epithet refers to the locality from where the type species was collected.

Holotype.

HKAS 128268.

Description.

Saprobic on the decayed wood. Sexual morph: Apothecia 2.3-4.2 mm wide (x̄ = 3.0 ± 0.6 mm, n = 15) when fresh, 1.2-2.0(-2.5) mm wide × 0.47-0.72 mm high (x̄ = 1.6 ± 0.3 × 0.58 ± 0.09 mm, n = 18) when dry, scattered or gregarious, disk-like with short stipitate, glabrous, developing on the surface of the substrate. Disc flat and circular, slightly convex at the center and downward at the edge when fresh, edge slightly curls inward towards the center, edge of large ascoma somewhat undulating, orange grey (5B2) to brownish grey (5C2) when fresh, dark brownish black or deep green (1D8) to olive (1E8) when dry. Margins concolorous to the disc when fresh, white to pale yellow or concolorous to the receptacles when dry. Receptacle dark brownish black or dark ochraceous-brown when dry, slightly rough and finely pustules when mature. Stipe 270-480(-650) μm wide × 190-400 μm long (x̄ = 400 ± 86 × 320 ± 76 μm, n = 18), short, regular cylindrical, concolorous to the receptacle or nearly black, almost smooth on the surface. Hymenium 173-227 μm (x̄ = 210 ± 17 μm, n = 15), hyaline. Subhymenium not obvious. Medullary excipulum 273-330 μm (x̄ = 307 ± 22 μm, n = 15) thick, well-developed, comprised of thin-walled, septate, pale brown and slightly loose hyphae of textura intricata, hyphae (3.5-)4.2-8.7 μm (x̄ = 6.2 ± 1.5 μm, n = 70) diam., hyaline, becoming dense near to the hymenium, darkening, dense and well-organized parallel near to the ectal excipulum, non-gelatinous. Ectal excipulum of the inner layers generally comprised of 3-6 layers vertically oriented textura angularis cells, 34-62(-77) μm (x̄ = 49 ± 10 μm, n = 60) thick, pale brown to hyaline toward inwards, cells of inner layers 10.5-18.5(-20.4) μm (x̄ = 14.0 ± 2.6 μm, n = 100) diam., wall (0.49-)0.65-1.09(-1.3) μm (x̄ = 0.87 ± 0.15 μm, n = 100) thick; proliferate 3-4 layers irregular-shaped and minimal textura angularis or textura prismatica cells, 4.0-8.4 μm (x̄ = 6.3 ± 1.3 μm, n = 100) diam., wall 0.59-0.94 μm (x̄ = 0.77 ± 0.12 μm, n = 70) thick; terminal cells at margin obviously elongated to 17-33 μm × 3.6-5.9 μm, slightly curved and soft, apex rounded and sometimes swollen, thin-walled, pale brown or hyaline. Paraphyses 1.9-3.3 μm (x̄ = 2.6 ± 0.5 μm, n = 70) wide, hyaline, filiform, rounded apex, 1-2-septate, unbranched, with conspicuous contents in Melzer’s reagent, scarcely extending beyond the asci. Asci (159.6-)167.4-190.7(-200.0) × 11.3-15.8 μm (x̄ = 177.5 ± 8.7 × 13.1 ± 1.2 μm, n = 30), unitunicate, 8-spored, cylindric or subclavate, apically rounded with an amyloid apical pore in Melzer’s reagent, thickened wall at apex, 7.2-11.5 × 3.0-5.7 (x̄ = 9.2 ± 1.5 × 4.2 ± 0.7 μm, n = 40), tapering to a pleurorhynchous subtruncate base, croziers present. Ascospore (24.1-)26.2-34.9(-36.5) × (6.3-)7.0-8.9(-9.5) μm (x̄ = 30.0 ± 2.8 × 7.9 ± 0.6 μm, n = 100), Q = (2.8-)3.2-4.6(-5.2), Qm = 3.8 ± 0.2, uniseriate, elongated ellipsoidal with a large guttule, slightly curved and asymmetrical on the lateral view, ends rounded, hyaline, thin-walled, smooth, aseptate, appearing 1-septate when germinating. Asexual morph: Undetermined.

Material examined.

China, Yunnan Province, Yuxi City, Xinping County, altitude 2090 m, on soft decayed unknown wood in managed plantation, 5 June 2022, Cuijinyi Li , LCJY-633 (HKAS 128268, holotype); ibid., altitude 2340 m, on decayed unknown wood, 6 June 2022, Cuijinyi Li, LCJY-634 (HKAS 128270, paratype) .

Notes.

The distinctive characteristics of T. yuxiensis are orange-grey to brownish-grey discs when fresh, dark brownish-black or dark ochraceous-brown when dry, short and regular cylindrical stipe, 3-4 layers of proliferous minimal cells, pleurorhynchous asci and elongated ellipsoidal and laterally asymmetrical ascospores.

Morphologically, T. yuxiensis resembles T. aseptata with their similar-sized and disk-like apothecia with a short stipe, filiform paraphyses, cylindric asci and ellipsoidal ascospores. In contrast to T. aseptata , T. yuxiensis has darker receptacles, regular cylindrical stipes, inconspicuous subhymenium, thicker medullary excipulum (273-330 μm vs. 120-145 μm) with larger terminal cells (17-33 μm × 3.6-5.9 μm vs. 13.1-15.3 μm × 2.6-3.8 μm) that almost appear as 3-4 layers of proliferous minimal cells and ascospores with higher length-width ratio (3.8 vs. 2.97). Furthermore, our collections of T. aseptata (HKAS 128265, HKAS 128269, HKAS 128271, HKAS 128274) have shorter asci (136.7-157.8 μm vs. 167.4-190.7 μm) and 8-12 layers of proliferous cells, compared to T. yuxiensis .

Phylogenetically, T. yuxiensis clustered sister to T. aseptata with 100% ML bootstrap support and 1.0 Bayesian probability in the combined LSU and ITS phylogeny (Fig. 2 ). The pairwise homoplasy index (PHI) indicated no significant genetic recombination (Φw = 1.0) between T. yuxiensis and T. aseptata and confirmed that they are different species (Fig. 3 ).

Figures

Figure 2. Maximum likelihood tree based on a combined dataset of LSU and ITS sequences for the genus Tatraea. The ML bootstrap proportions (ML-BP) equal to or higher than 70 % and Bayesian posterior proportions (BI-PP) equal to or higher than 0.90 are shown near the branches on the phylogenetic tree. Newly generated isolates of the current study are shown in blue and ex-types are shown in bold.

Figure 3. The results of the pairwise homoplasy index (PHI) test for the closely related species in Tatraea using LogDet transformation. A. PHI test for Tatraea yunnanensis vs. Tatraea macrospora. B. PHI test for Tatraea yuxiensis vs. Tatraea aseptata. C. PHI test for T atraea Tatraea clepsydriformis vs. Tatraea griseoturcoisina. PHI test results (Φw <0.05) indicate significant recombination within the dataset.

Figure 8. Tatraea yuxiensis (HKAS 128268, holotype) a fresh ascomata on the wood b-e dried ascomata on the wood f vertical section of an ascoma g-i excipulum j-k paraphyses l-o asci (o-p asci in Meltzer's reagent) p-v ascospores. Scale bars: 1.5 mm (b); 700 μm (d-c); 400 μm (e); 800 μm (f-g); 1000 μm (h); 200 μm (i); 100 μm (j); 70 μm (k-p); 15 μm (q-v).