Dermoloma vestigium Adamčík & Corriol, 2025

Adamčíková, Katarína, Kiran, Munazza, Caboň, Miroslav, Matheny, Brandon P., Sánchez-García, Marisol, Arnolds, Eef, Caboňová, Michaela, Corriol, Gilles, Dima, Bálint, Friebes, Gernot, Griffith, Gareth W., Grootmyers, Django, Harries, David, Karich, Alexander, Mešić, Armin, Mihaljevič, Martin, Moreau, Pierre-Arthur, Pošta, Ana, Shapkin, Vasilii, Tkalčec, Zdenko, Vizzini, Alfredo, Vondrovicová, Lenka, Adamčík, Slavomir & Jančovičová, Soňa, 2025, A phylogenetic and morphological study of the genus Dermoloma (Agaricales, Tricholomataceae) in Europe and North America exposes inefficiency of opportunistic species descriptions, IMA Fungus 16, pp. e 157337-e 157337 : e157337-

Dermoloma vestigium Adamčík & Corriol sp. nov.

Figs 48 e, f , 53

Etymology.

Type collected in hoof prints of cows at a pasture entrance.

Holotype.

Slovakia • Zvolenská kotlina Basin, pasture E of the village Bečov , elev. 400–450 m, coord. 48°38'48"N, 19°14'49"E, terrestrial at the entrance to the pasture on soil disturbed by cattle hoof prints, 17 Sep 2020, S. Adamčík ( SAV F-20662 ).

Diagnosis.

European species; basidiomata formed by this species are the smallest known in the genus; pilei up to 10 mm in diameter; stipes up to 1.5 mm wide; lamellae light brown to dark brown; spores amyloid 5.3–6.2 × 3.5–4.4 μm; caulocystidia on average <30 µm long and> 8 µm wide.

Pileus (2 –) 4–8 (10) mm; when young semiglobose, soon convex to plano-convex, often indistinctly umbonate; margin translucently striate to half of the radius when wet; surface usually smooth, sometimes rugulose, slightly hygrophanous; color near margin brown (5 E 4,6E 4, 5 F 7) to dark brown (6 F 4, 6 F 5, 7 F 3, 7 F 4, 7 F 4), near center dark brown (6 F 2, 6 F 3, 6 F 4, 6 F 5) to black, when dry uniformly grayish brown (5 D 3, 6 D 3,6E 3), light brown (5 D 4) to brown (6 E 4,6E 5). Stipe (8 –) 10–25 (– 30) × 0.5–1.5 mm; cylindrical, flexuous, grooved; surface finely pruinose near lamellae, glabrous and shiny towards the base; color near lamellae grayish brown (5 D 3), light brown (5 D 5), brown (5 E 5,6E 4,6E 5), near the base dark brown (6 F 4, 6 F 5, 8 F 4). Lamellae L = (10 –) 17–20, l = (0 –) 1–3; 0.5–2 mm wide; adnate-emarginate and decurrent with tooth; color grayish brown (5 D 3,6E 3,7E 3), light brown (5 D 4), brown (6 E 4,6E 5) to dark brown (6 F 4, 7 F 3); edges entire. Context elastic or fragile; odor farinaceous, sometimes weakly.

Spores (4.3 –) 5.3–5.7 – 6.2 (– 6.8) × (3.1 –) 3.5–4 – 4.4 (– 5.1) μm; ellipsoid to oblong, Q = (1.22 –) 1.35–1.45 – 1.56 (– 1.89); walls amyloid, few dispersed spores thick-walled and dextrinoid; hilar appendage 0.5–0.8 μm long. Basidia (17 –) 18.5–20.8 – 23 (– 27) × (4.5 –) 5–6 – 7 (– 8.5) μm; clavate; with 2 sterigmata or with 2 and 4 sterigmata, occasionally also with 1 or 3 sterigmata. Basidioles first cylindrical, then clavate, ca. 3–6 μm wide. Marginal cells (11 –) 17–20.1 – 23 (– 30) × (2.5 –) 3–4 – 4.5 (– 7) μm; mainly cylindrical or lageniform, occasionally narrowly fusiform, flexuous, occasionally nodulose or slightly moniliform, apically often constricted or with an appendage. Pileipellis 70–90 μm deep; suprapellis 35–45 μm deep, usually of one or two layers of inflated, densely arranged cells; subpellis well-differentiated, 35–55 μm deep, of densely packed, puzzled, irregularly oriented, 2.5–10 μm wide hyphae, sharply delimited from horizontally oriented hyphae in trama; hyphal terminations with yellow-brown parietal pigments, sometimes also incrusted and locally with darker brown pigments, walls thickened up to 0.5 μm, near septa of terminal cells and in subpellis up to 1 μm. Terminal cells near pileus margin (13 –) 23.5–32.7 – 42 (– 54) × (9 –) 11.5–14.7 – 18 (– 22.5) μm; usually obpyriform or sphaeropedunculate, occasionally clavate or subglobose; subterminal cells often branched, cylindrical, fusiform or clavate, often inflated-ventricose, often with lateral swellings, branches or lobate. Terminal cells near pileus center (17 –) 24.5–31.8 – 39 (– 49) × (9 –) 11.5–15.4 – 19.5 (– 30) μm; subglogose, obpyriform, clavate or ellipsoid; subterminal cells often branched, mainly ellipsoid or fusiform-ventricose, often lobate. Caulocystidia (6 –) 12.5–19.3 – 26 (– 38) × (3.5 –) 5.5–8.6 – 11.5 (– 16) μm; variable, cylindrical, clavate, obpyriform, sphaeropedunculate, subglobose, ellipsoid, usually in dense clusters, erect or ascending, subterminal cells often inflated; thin-walled or slightly thickened up to 0.5 μm, with brown parietal and sometimes also incrusted pigments. Clamp connections present.

Distribution and ecology.

Known from Finland, France, Germany and Slovakia; in semi-natural grasslands on acidic to calcareous soil, once found in a calcareous forest. Several collections, including the holotype, grew on disrupted soil in or around hoof prints.

Additional material studied.

Finland • Laatokan Karjala, Saari, church yard , coord. 61°39'11"N, 29°44'46"E, in open site in forest with Picea abies , Pinus sylvestris , Betula , Salix caprea and Salix sp. , on calcareous ground, gravel soil, 24 Sept 2004, J. Vauras FISAP 923-14 ( TUR 170268 ) . France • Hautes-Pyrénées, Bagnères-de-Bigorre, Cérétou , coord. 42°59'23"N, 00°05'44"E, acidophilic grazed grassland (Nardion), 11 Oct 2014, G. Corriol GC 14101103 ( BBF, as D. pseudocamarophyllopsis ) . Germany • Rheinland-Pfalz, Horbach , elev. 370 m, coord. 49°49'44"N, 07°31'17"E, terrestrial on grassland entrance, 8 Nov 2019, S. Adamčík ( SAV F-20505 ) . Slovakia • Laborecká vrchovina Mts., pasture 1 km SSE of Osadné , elev. 400 m, coord. 49°08'07"N, 22°09'10"E, terrestrial, 12 Aug 2011, S. Adamčík ( SAV F-4102 ) ; • Zvolenská kotlina Basin, pasture E of the village Bečov , elev. 400–450 m, coord. 48°38'48"N, 19°14'49"E, terrestrial, 17 Sep 2020, S. Adamčík ( SAV F-20663 ) ; • ibid., 17 Sep 2020, S. Adamčík ( SAV F-20664 ) .

Notes.

Dermoloma vestigium is a member of D. subgenus Amylospora , section Atrobrunnea . It is among the smallest Dermoloma species known. Unique characters of this species are the short and relatively broad caulocystidia contrasting with the narrow apically constricted marginal cells. The sister species D. rostratum (Fig. 2 ) also has small basidiomata, but it is clearly distinguished by the narrower caulocystidia and often nodulose marginal cells. The species was included in the phylogenetic study by Sánchez-García and Matheny (2017) as “ Dermoloma sp. ” but was incorrectly labelled as SAV 4103. Later, the same sample was correctly labelled as SAV F- 4102 in Sánchez-García et al. (2021) as “ Dermoloma sp. 6 ”. The holotype is selected with respect to the best set of DNA regions and sufficient amount of basidiomata.

Figures

Figure 2. Phylogram generated by ML analysis based on combined sequence data of ITS, LSU, rpb 1, rpb 2, mcm 7 and tef 1 a showing phylogenetic relationships within genus Dermoloma. ML bootstrap support values greater or equal to 50 % and Bayesian posterior probabilities greater or equal to 0.90 are indicated above or below the nodes. Sequences originating from type collections are labelled in red and bold.

Figure 48. Basidiomata of Dermoloma in field appearance. a Dermoloma rostratum (CNF 5 / 209), photo A. Mešić; b Dermoloma rostratum (GLM-F 137760), photo A. Karich; c Dermoloma simile (SAV F- 4421, holotype), photo D. Harries; d Dermoloma simile (CNF 1 / 5620), photo A. Mešić; e Dermoloma vestigium (SAV F- 20662, holotype), photo S. Jančovičová; f Dermoloma vestigium [BBF (GC 14101103)], photo G. Corriol. Scale bar: 10 mm.

Figure 53. Dermoloma vestigium (SAV F- 4102), microscopic elements. a Spores; b caulocystidia; c basidia and basidioles; d marginal cells; e pileipellis elements near the pileus margin; f pileipellis elements near the pileus center. Scale bar: 5 µm for spores and 10 µm for other elements.