Lyomyces neocrustosus 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 neocrustosus Yurchenko & Riebesehl sp. nov.

Figs 3 G, H , 7 , 16 E

Type.

Panama • Chiriquí Province: Bajo Mono NW of Boquete, southern slopes of Cordillera de Talamanca, near the Caldera River , 08 ° 50.00 ' N, 082 ° 28.83 ' W, about 1650 m a. s. l., edge or evergreen mountain rainforest, on small-sized dead trunk, mostly on the decorticated parts, 28 Jul 2019, E. Yurchenko EYu 190728-14 (holotype: BLS M-5239 ; isotype: CFMR). GenBank: ITS = PP 471801; 28 S = PP 471821 .

Etymology.

neo + crustosus (Lat.) = (1) new in L. crustosus species complex, (2) a neotropical species, close to L. crustosus .

Description.

Basidiomata effused, 1.5–3 and more cm in extent, adnate, 25–110 μm thick excluding warts, membranaceous to subceraceous. Hymenial surface pale cream, white at the periphery, smooth to sparsely and minutely warted; warts up to 3–5 / mm, 20–70 μm high. Margin paler than the main surface, from almost abrupt and pubescent to thinning out, 0.3–0.5 (– 1) mm wide. Hyphal system monomitic, hyphae clamped at all septa, thin-walled, colourless. Rosette-like crystals present in moderate or rich amounts between hyphae and hymenial elements. Subicular hyphae moderately branched, 2–3 μm wide; subhymenial hyphae richly branched, densely packed, 1.3–3.7 (– 4.5) μm wide. Subulate cystidia common, 16–25 × 2.5–3.5 (– 4.5) μm, seldom capitulate apically, smooth or slightly encrusted. Cylindrical cystidia rare, 18–21.5 × 2.7–3.5 μm. Basidioles narrowly ovoid to short clavate, seldom cylindrical, 11.5–18 × 3.8–4.5 (– 5.3) μm. Basidia subcylindrical to utriform, (13.5 –) 16–22.5 × (3.7 –) 4–4.5 (– 5.3) μm; sterigmata four, 2.5–5 × 0.7 μm. Basidiospores narrowly ellipsoid to oblong, (5.3 –) 5.5–6 (– 6.5) × (2.5 –) 3–3.5 μm (in holotype L = 5.75 μm, W = 3.2 μm), Q = (1.5 –) 1.7–1.8, thin- to slightly thick-walled (wall 0.3 μm thick), smooth, colourless, often with a large drop inside, Mz –, acyanophilous; apiculus short, but distinct.

Distribution.

Known from Panama and Colombia.

Ecology.

The species grows on dead wood in evergreen tropical forests.

Notes.

This species differs from L. crustosus by virtue of sparse and little-developed hymenophoral projections, the paler colour of the hymenial surface, thin-walled hyphae, shorter subulate cystidia, shorter basidioles, and broader, often slightly thick-walled basidiospores with a straight or convex adaxial side. In the two examined specimens, referred by us to L. crustosus s. str. ( KAS-GEL 2325 , KAS-GEL 5360 ; Fig. 1 ), the subulate cystidia were (20 –) 25–40 (– 50) μm long, basidioles were clavate to cylindrical, (13.5 –) 15–25 μm long, and basidiospores were 2.5–2.8 (– 3) μm wide, thin-walled, with straight or slightly concave adaxial side (in KAS-GEL 5360 L = 5.6 μm, W = 2.7 μm). According to the illustrations in Eriksson and Ryvarden (1976), in L. crustosus , subulate cystidia are 22–40 μm long, and basidia are 23–33 μm long, which is about 1.5 times longer than in L. neocrustosus .

Additional specimens examined.

Lyomyces neocrustosus — Colombia • Magdalena Department: Tayrona National Natural Park, Estación de Gairaca , on dead corticated wood, 12 Jun 1978, L. Ryvarden 15737 (O-F- 918425, paratype).

Lyomyces crustosus — Germany • Bayern: Oberallgäu district, Hinterstein vicinity, about 850 m a. s. l., on a dead twig of cf. Fraxinus excelsior , 19 Sep 1991, G. Langer, E. Langer ( KAS-GEL 2325 ) • Hinterstein vicinity, about 1060 m a. s. l., on dead wood of Fagus sylvatica , 14 Oct 1998, E. Langer, E. Hennen ( KAS-GEL 5360 ).

Figures

Figure 1. Bayesian reconstruction of the phylogeny for the Lyomyces species based on ITS sequences. Numbers above branches denote posterior probability values (PP ≥ 0.9) / ML bootstrap values (BS ≥ 75 %) from the ML phylogram; ‘ - ’ denotes the absence of the branch in the ML phylogram. Sequences obtained in this study are shown in bold. Scale bar: number of substitutions per site.

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 7. Micromorphology of Lyomyces neocrustosus (holotype, BLS M- 5239) A, B vertical sections through basidioma C subicular hyphae D Subhymenial hyphae ended by cystidia and basidioles E cystidia F basidioles G basidia H basidiospores. Scale bars: 20 μm (A, B); 10 μm (C – G); 5 μm (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.