Lyomyces orarius Yurchenko & Riebesehl 2024, sp. nov.
Creators: name: Yurchenko, Eugene
name: Langer, Ewald
name: Riebesehl, Janett
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Corticiales
Hymenochaetales
Lyomyces
Lyomyces orarius

description: 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).
description: Published as part of 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, pp. 131-169 in MycoKeys 109 on pages 131-169, DOI: 10.3897/mycokeys.109.127606