Lyomyces granulosus Yurchenko & Langer 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 granulosus

description: Lyomyces granulosus Yurchenko & Langer sp. nov.
Figs 3 C, D, 5, 16 C
Type.
Costa Rica • Alajuela Province: near Fraijanes and Poás volcano, 1940 m a. s. l., secondary evergreen tropical forest in a ravine, on wood and bark of dead branch or stem 30 mm in diam., 11 Feb 1989, E. Langer, G. Wagner No. 223 (holotype: KAS-GEL 1662; isotype: CFMR). GenBank: ITS = PP 471799.
Etymology.
granulosus (Lat.) = having a grainy structure, due to the morphology of basidioma.
Description.
Basidiomata effused, 0.1–3 cm in extent, grandinioid-farinaceous to membranaceous, soft and fragile, usually consisting of as-if-confluent grains, 50–115 μm thick. Hymenial surface colliculose, whitish or creamish. Margin concolourous, pruinose, diffuse, 0.3–1 mm wide. Hyphal system monomitic, hyphae clamped at all septa, thin-walled, colourless. Subiculum thin, little differentiated from subhymenium. Subicular hyphae moderately branched, comparatively short-celled, 1.8–3.5 (– 4) μm wide, smooth; subhymenial hyphae richly branched, 2–3.2 μm wide, smooth or scarcely encrusted. Cystidia of several types: 1) capitate and subcapitate common, 15–47 × 4–5.5 μm, often with several slight constrictions, smooth to richly encrusted in the lower 2 / 3 of their length; 2) fusoid and subcylindrical scattered, 30–55 × 3–4.5 (– 6) μm, smooth to richly encrusted. Basidioles mostly clavate, 7.5–20 × 3.5–5 (– 6) μm, smooth. Basidia 14–19 × 4.5–4.7 μm, smooth, with four sterigmata 2–3 × 0.5–0.7 μm. Basidiospores broadly ellipsoid, (4.5 –) 5–5.5 (– 6.3) × (3.3 –) 3.5–4 μm (in holotype L = 5.1 μm, W = 3.7 μm), Q = 1.2–1.4 (– 1.6), thin- to often slightly thick-walled, smooth, colourless, Mz –, acyanophilous to slightly cyanophilous; apiculus small, but distinct.
Distribution.
So far, known from Costa Rica and Panama.
Ecology.
The species grows on dead decorticated small-sized wood in evergreen tropical forests, with a supposed preference for mountain ravines.
Additional specimens examined
(paratypes). Costa Rica • The same locality as holotype, on wood and bark of dead stem 7–15 mm in diam., 11 Feb 1989, E. Langer, G. Wagner (KAS-GEL 1650); Panama • Chiriquí Province: W of Boquete town, Bajo Boquete community, 08 ° 46.58 ' N, 082 ° 28.17 ' W, 1450 m a. s. l., evergreen montane tropical forest, bottom of canyon with a rivulet, on a decorticated fallen branch, 27 Jul 2019, E. Yurchenko EYu 190727-8 b (BLS M-2975; GenBank: ITS = PP 471798, 28 S = PP 471819).
Notes.
The main diagnostic features of this species are the granulose structure of basidioma, thin-walled hyphae, presence of slightly constricted capitate cystidia, and broadly ellipsoid basidiospores with thin or slightly thickened walls. The species is morphologically close to L. sambuci, L. denudatus, and L. fimbriatus. In contrast to the new species, L. sambuci has less encrusted capitate cystidia and spores often with a drop inside. Lyomyces fimbriatus and L. denudatus have larger, thin-walled spores. Moreover, L. fimbriatus has an odontoid hymenial surface.
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