Lyomyces napoensis Yurchenko & Riebesehl, 2024

Yurchenko, Eugene, Langer, Ewald & Riebesehl, Janett, 2024, A high species diversity of Lyomyces (Basidiomycota, Hymenochaetales) in Central and South America, revealed after morphological and molecular analysis, MycoKeys 109, pp. 131-169 : 131-169

Lyomyces napoensis Yurchenko & Riebesehl sp. nov.

Figs 3 E, F , 6 , 16 D

Type.

Ecuador • Orellana Province: between Puerto Francisco de Orellana (El Coca) and El Dorado, right bank of the Napo River , 00 ° 29.17 ' S, 076 ° 57.00 ' W, 260 m a. s. l., Amazonian rainforest, on dead standing lignified stem, 20 Jul 2019, E. Yurchenko EYu 190720-18 (holotype: BLS M-2610 ; isotype: CFMR). GenBank: ITS = PP 471800; 28 S = PP 471820 .

Etymology.

The epithet refers to the Napo River, near which the type specimen was collected.

Description.

Basidiomata effused, 0.3–3.5 cm in extent, pruinose and mostly discontinuous to soft membranaceous, 45–90 μm thick. Hymenial surface dirty pale ochraceous, smooth to minutely warted; warts 3–5 / mm, 30–45 μm high. Margin pruinose, diffuse (indeterminate), 0.3–2.5 mm wide. Hyphal system monomitic, hyphae moderately branched, clamped at all septa, thin-walled, colourless, smooth or encrusted. Cystidia and basidioles smooth to richly encrusted. Cystidia of several types: 1) capitate common, 15–35 × 3–5.5 μm, loosely encrusted except for capitate apex; 2) clavate cystidia with dark yellow granulose contents common, immersed, 12–23 × 5–7 μm; 3) fusoid and hyphoid cystidia rare or occasional, 18–26 × 4.3–5.5 μm. Basidioles short clavate to subcylindrical, 7.5–22 × 3–6 (– 7.3) μm, often with oily inclusions. Basidia utriform-cylindrical, 15.5–25 × 5.5–6.7 μm, slightly encrusted, with (2) 4 sterigmata measuring 4–5 × 0.5–1 μm. Basidiospores narrowly ellipsoid to oblong, with adaxial side straight or slightly concave, 7–8.5 (– 9) × 4–4.7 μm (L = 7.1 μm, W = 4.4 μm), Q = 1.5–1.7, thin-walled, smooth, colourless, with oily inclusions, Mz –, acyanophilous; apiculus short and wide, or not pronounced.

Distribution.

So far, known from the northeast part of Ecuador, in the Amazonian Lowland.

Ecology.

The fungus grows on dead lignified stems, in equatorial rainforests.

Notes.

The species is distinguished from other members of Lyomyces by encrusted capitate cystidia, basidioles, and basidia, presence of clavate cystidia with dark yellow granulose contents, and by large, oblong, thin-walled basidiospores with oily contents. This species is morphologically close to L. incrustatus and L. elaeidicola because of the minute attached incrustation on basidioles and basidia. However, the two latter species have near-globose basidiospores.

Figures

Figure 3. Macromorphology of Lyomyces species A, B L. boquetensis, holotype (BLS M- 5238) C L. granulosus, holotype (KAS-GEL 1662) D L. granulosus, BLS M- 2975 E, F L. napoensis, holotype (BLS M- 2610) G, H L. neocrustosus, holotype (BLS M- 5239). Scale bars: 1 mm.

Figure 6. Micromorphology of Lyomyces napoensis (holotype, BLS M- 2610) A, B vertical sections through basidioma C subicular hyphae D cystidia E basidioles in KOH F basidioles in Mz G basidia H basidiospores. Scale bars: 100 μm (A); 10 μm (B – H).

Figure 16. SEM of crystalline deposits on hymenial elements and hyphae in holotypes of Lyomyces species A, B L. boquetensis C L. granulosus D L. napoensis E L. neocrustosus F L. pantropicus G L. parvus H L. subcylindricus. Scale bars: 5 μm.