Lentaria variabilis M. Villegas, R. Garibay-Orijel & N. Matías-Ferrer, sp. nov.

Index Fungorum number: IF 828899; MycoBank number: MB 828899; Facesoffungi number: FoF 05496; Fig. 1

Etymology – From latin variabilis, variable, referring to its variation in color and branch position.

Holotype – FCME 21524.

Basidiocarps gregarious, annual, 20–75 mm in length. Subiculum and mycelial chords whitish, up to 2 mm thick, generally immersed in the substrate, rarely superficial. Stipe 10–35×1–7 mm, subcylindrical, pale yellow, greyish orange with brown tones to reddish brown (4A3, 5B3, 5C4, 7D3, 8/4 10YR). Branching up to five levels, predominantly dichotomous, cylindrical to slightly fattened, internode space reduces gradually towards the apex; parallel or a bit loose, pale yellow, orange-grey with brown or light brown tones (4A3, 6B2, 6C3, 7C–D4), rounded internodes and smooth surface. Apices acute, white or pale yellow with orange tones of different intensity (5A2–6C4). Sub-leathery consistency, easily broken when dry; context concolorous with surface. Smell not distinct. Taste slightly sour or astringent favor. Hyphal system monomitic, thick-walled hyphae, conspicuously fibulate; occasionally ampulliform fibulae up to 15 μm width. Subiculum and mycelial chords with hyphae 1–5 μm width, covered with numerous crystals irregularly shaped, easily detachable. Branch context with hyphae 3–8 μm thick and occasional H connections. Hymenium thickened, amphigenous; basidia sub-claviform, hyaline, tetrasporic, sterigmata 2–10 μm long, fibulate at the base, homogeneous content or sometimes uni to multiguttulate, 20–74×6–11 µm. Spores subcylindrical to subsigmoid, smooth, thin-walled, (8–)10–15×2–5 µm, L=11.7 µm, W=2.7 μm Q=3.13 µm (n=30/1), remain together in groups of four after basidium detachment.

Habitat and distribution – Lignicolous, growing in highly decomposed wood in sub-perennial tropical forest, alt. 100–250 m.

Material examined – MEXICO, Campeche, Calakmul municipality, Km 26 Escárcega-Chetumal highroad, Calakmul archaeological site deviation, 18°18′02″ N, 89°50′47″ W, 25 September 2003, Villegas-Ríos M. 2429 (FCME 21524, holotype); ibid. 27 October 2002, García-Sandoval 2002–2034 (FCME 19864); ibid. 1 November 2001, GarcíaSandoval 2001–63 (FCME 19862). Archaeological site Xpuhil, 19 September 2003, Villegas-Ríos M. 2382 (FCME 21518); ibid. 20 September 2003, Villegas-Ríos M. 2390 (FCME 21520); ibid. 28 October 2002, García-Sandoval 2002–42 (FCME 19861). Km 25.5 Escárcega-Chetumal highroad, on the exit to Union 20 de Agosto, 22 September 2003, Villegas-Ríos M. 2408 (FCME 21522); ibid. 25 September 2003, Villegas-Ríos M. 2431 (FCME 21525); ibid. Villegas-Ríos M. 2434 (FCME 21526); ibid. 25 October 2002, Villegas-Ríos M. 2274 (FCME 21516).

GenBank numbers – ITS: MK253189, MK253185, MK253184, MK253192, MK253186, MK253191, MK253193, MK253188, MK253194, MK253187; LSU: MK253215, MK253206, MK253205, MK253211, LSU: MK253213, MK253207, MK253214, MK253216, MK253217, MK253210.

Notes – As its epithet says, Lentaria variabilis is morphologically variable as is evident from the various forms of basidiocarp branching, coloration and subiculum position. However, its microscopic characters are homogeneous regarding spores, basidia and hyphal shape and size. Molecular data also showed that, despite this macro-morphological variation, all sequenced individuals belong to a monophyletic group of an independent lineage (Fig. 2) of tropical species. Some light-colored specimens of L. variabilis resemble L. surculus Corner. However, spores of the latter are smaller (8.6–12.6×2.9–4 μm, Petersen 2000).

Figure 1 –  Basidiocarps of Lentaria variabilis (Pictures, J. Cifuentes). a (FCME 21524, holotype). b (FCME 21520). c (FCME 21520). Microscopic structures (FCME 21524, holotype) d Basidia, basidiole and basidiospores. e Subiculum hyphae. f Ampulliform fibula. Scale bars: a–c=10 mm, d=20 μm, e–f=10 μm

Figure 2 –  Majority-rule consensus tree of Lentaria gossypina, L. variabilis and reference sequences using a ITS and LSU concatenated matrix. Bayesian posterior probabilities (PP)≥0.84 and bootstrap support values (ML)≥70% are labeled. Type material for the new species are in bold. Outgroups are Dyctiophora rubrovolvata and Clathrus ruber