Lyomyces orarius 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 orarius Yurchenko & Riebesehl sp. nov.

Figs 8 B , 10

Type.

Ecuador • Esmeraldas Province: NW of Esmeraldas town, Pacific Ocean shore , 00 ° 59.13 ' N, 079 ° 40.15 ' W, 5–10 m a. s. l., semi-xerophytic bush vegetation on a coastal hill, on the bark of a dead stump, 24 Jul 2019, E. Yurchenko EYu 190724-1 (holotype: BLS M-2995 ; isotype: CFMR). GenBank: ITS = PP 471805; 28 S = PP 471822 .

Etymology.

orarius (Lat.) = occurring on seashore, referring to the geography of type locality.

Description.

Basidiomata effused, 3–20 mm in extent, 70–100 μm thick, soft-membranaceous, porulose to minutely grandinioid; hymenial surface white or greyish; margin almost abrupt to diffuse, and then up to 0.3 mm wide. Hyphal system monomitic, hyphae clamped at all septa, moderately branched, colourless. Subiculum loose; subicular hyphae 1.8–3.2 µm wide, often branched at a right angle, with thin- or slightly-thickened walls, naked or slightly encrusted. Subhymenial texture mostly masked by crystalline material; subhymenial hyphae 2–4 µm wide, thin-walled. Cystidia of several types: 1) capitate, subcapitate, capitulate, often projecting, 15–37 × 3.3–4 μm, moderately to richly encrusted in the lower 2 / 3 s of their length, rarely naked, capitate / capitulate ends 2–3 μm wide, occasionally with a cap of resinous matter 4–6 μm wide, the latter easily detached in preparation; 2) cylindrical, 15–33 × 3–3.5 μm; 3) tapering, hypha-like, supposedly the collapsed stages of capitate and cylindrical variants, 20–33 × 2.7–3.2 μm. Basidioles irregularly cylindrical to subclavate, 8.5–12.5 × 3–3.8 μm, smooth to richly encrusted. Basidiospores ellipsoid to narrowly ellipsoid, 4.3–5 (– 5.5) × (2.5 –) 2.8–3.2 (– 3.5) µm (L = 4.55 µm, W = 3.1 µm), Q = 1.5–1.7, with thin- or unclearly thickened wall, smooth, colourless, sometimes with a drop inside; apiculus minute or indistinct.

Distribution.

So far, known from the northwest of Ecuador.

Ecology.

The species grows on dead corticated wood in tropical monsoon semi-deciduous forests and bushes.

Notes.

Mature basidia with sterigmata were not found in the holotype. The species is most morphologically close to L. sambuci and L. bambusinus . The new species is distinguished from L. sambuci by smaller, mostly thin-walled basidiospores and the presence of capitulate cystidia, richly encrusted in the lower 2 / 3 s of their length. In contrast to L. orarius , L. bambusinus has thick-walled hyphae, little-encrusted capitate cystidia, long (40–65 μm) tapering cystidia, subulate cystidioles (12–17 μm long), and larger (up to 6.2 × 4.8 μm) spores with constantly thickened walls ( Chen and Zhao 2020).

Figures

Figure 8. Macromorphology of Lyomyces species A L. oleifer, holotype (KAS-Ec 47-2001) B L. orarius, holotype (BLS M- 2995) C L. pantropicus, holotype (BLS M- 2679) D L. pantropicus, BLS M- 3545 E L. parvus, holotype (KAS-GEL 1599) F L. parvus, BLS M- 2990 G L. sceptrifer, holotype (KAS-Ec 661-2002) H L. subcylindricus, holotype (BLS M- 2668). Scale bars: 1 mm.

Figure 10. Micromorphology of Lyomyces orarius (holotype, BLS M- 2995) A, B vertical sections through basidioma C subicular hyphae D capitate cystidia in KOH E capitate cystidia in Mz F capitulate cystidia G cylindrical and tapering cystidia H caps of resinous matter detached from capitate cystidia I basidioles J basidiospores. Scale bars: 20 μm (A, B); 10 μm (C – G, I); 5 μm (H, J).