Lyomyces boquetensis 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 boquetensis Yurchenko & Riebesehl sp. nov.

Figs 3 A, B , 4 , 16 A, B

Type.

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 fallen corticated twig of angiosperm, 27 Jul 2019, E. Yurchenko EYu 190727-12 (holotype: BLS M-5238 ; isotype: CFMR). GenBank: ITS = PP 471797; 28 S = PP 471818 .

Etymology.

boquetensis = refers to Boquete, the town near the type locality.

Description.

Basidiomata effused, 1.5–3 and more cm in extent, soft-membranaceous to membranaceous, from fine flocculose or granulose and discontinuous when young to continuous, 20–60 μm thick between warts. Hymenial surface white or dirty whitish, smooth to minutely warted; warts up to 3–7 / mm, 15–60 μm high. Margin concolourous, appressed mould-like or diffuse, about 0.5 mm wide. Hyphal system monomitic, hyphae clamped at all septa, smooth (in KOH) or slightly encrusted (in Mz). Subiculum of loose texture; subicular hyphae moderately branched, 2–4 μm wide, thin- to somewhat thick-walled (walls up to 0.7 μm thick). Subhymenium thin; subhymenial hyphae richly branched, 2–3.7 μm wide, thin-walled. Cystidia thin-walled, colourless, smooth to heavily encrusted, of four types: 1) capitate scarce to common, 15–30 × 3.5–5 μm; 2) capitulate not frequent, 23–35 × 3–4.5 μm; 3) cylindrical and subcylindrical scattered, 20–28 × 3–4.3 μm; 4) fusoid rare, 25–35 × 4.5–5 μm. Incrustation on cystidia and basidioles partly dissolving in KOH. Basidioles short cylindrical to clavate, 10–13 × (3 –) 3.5–4.7 μm, smooth or slightly encrusted. Basidia cylindrical-utriform, 10.5–15.5 × 3.2–4 μm, smooth or slightly encrusted; sterigmata four, reaching 2.5–3 × 0.3–0.5 μm. Basidiospores ellipsoid to narrowly ellipsoid, 4–5 (– 5.5) × 2.7–3 (– 3.5) μm (L = 5.1 μm, W = 3.3 μm), thin-walled, smooth, colourless, some with a drop inside, Mz –, acyanophilous; apiculus minute, short.

Distribution.

So far, only known from Panama.

Ecology.

The species grows on small-sized dead corticated wood in tropical evergreen forests.

Notes.

The main diagnostic features of this species are a minutely warted hymenial surface, thickened walls in the subicular hyphae, the presence of smooth to heavily encrusted capitate and cylindrical cystidia, and thin-walled, narrowly ellipsoid basidiospores. This species is most morphologically similar to L. sambuci , L. densiusculus , and L. denudatus . It differs from L. sambuci s. str. by the presence of heavily encrusted capitulate cystidia and thin-walled basidiospores. The presence of richly encrusted capitulate cystidia and smaller basidiospores are the characteristics which separate L. boquetensis from L. densiusculus . Warted hymenial surface, cylindrical cystidia, and smaller basidiospores differentiate the new species from L. denudatus . The new species differs from a phylogenetically close L. lancangjiangensis by shorter and narrower 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 4. Micromorphology of Lyomyces boquetensis (holotype, BLS M- 5238) A, B vertical sections through basidioma C subicular hyphae D hyphae from hymenophore wart, ended by capitate cystidia E portion of hymenium and subhymenium F, G capitate and subcapitate cystidia H, I capitulate cystidia J cylindrical cystidia K, L basidioles M basidia N basidiospores. B – E, G, I, J, L – N in KOH; F, H, K in Mz. Scale bars: 100 μm (A); 10 μm (B – M); 5 μm (N).

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.