Dermoloma pusillum Contu

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 pusillum Contu , in Contu, Consiglio & Setti, Micol. Veg. Medit. 22 (2): 105. 2008.

Fig. 47

Holotype.

Italy • Sardinia, near Olbia, Pittulongu , 19 Dec 2006, F. Bocianolo 30 - XII- 2006 ( AQUI).

Distinguishing characters.

European species; basidiomata small, mycenoid; spores amyloid, broadly ellipsoid to narrowly ellipsoid, up to 6.5 μm long; caulocystidia large, 25.5–46 × 9.5–15.5 μm, clavate, sphaeropedunculate or obpyriform, known only from Mediterranean areas of Europe.

Basidiomata not collected by authors of this study, for description see original description ( Contu et al. 2008).

Spores (5.4 –) 5.7–6 – 6.4 (– 6.7) × (3.7 –) 4.3–4.6 – 4.8 (– 5.3) μm; broadly ellipsoid to narrowly ellipsoid, Q = (1.19 –) 1.25–1.32 – 1.39 (– 1.51); walls amyloid; hilar appendage ca. 1–1.5 μm long. Basidia (25 –) 26.5–28.5 – 30.5 (– 34) × (5 –) 5.5–6.2 – 7 (– 8) μm; clavate, cylindrical or fusiform; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 3.5–6 μm wide. Marginal cells (10 –) 15–18.6 – 22 (– 25) × (2 –) 4–6.1 – 8.5 (– 11) μm; clavate or cylindrical, flexuous, often lobate, apically mainly obtuse but often also constricted. Pileipellis 40–58 μm deep; suprapellis 30–40 μm deep, mainly of one layer of inflated, densely arranged cells; subpellis not well-differentiated, 16–20 μm deep, of densely packed, mainly horizontally oriented, intricate, branched, 2–5 (– 10) μm wide hyphae gradually passing to horizontally oriented hyphae in trama; hyphal terminations with brownish yellow parietal pigments, usually thin-walled or with slightly thickened walls up to 0.7 μm. Terminal cells near pileus margin (20 –) 29.5–38.1 – 46.5 (– 58) × (9 –) 15–19.5 – 24 (– 30) μm; mainly sphaeropedunculate, occasionally obpyriform or clavate, near septa flexuous, and sometimes nodulose; subterminal cells usually narrower and subcylindrical, occasionally clavate or fusiform, often branched or nodulose, flexuous. Terminal cells near pileus center (24 –) 33–43.3 – 54 (– 71) × (10 –) 15.5–21 – 26.5 (– 30) μm; mainly clavate, often also sphaeropedunculate, more distinctly clavate and nodulose towards septa; subterminal cells similar to cells near margin. Caulocystidia (24 –) 25.5–35.8 – 46 (– 78) × (7 –) 9.5–12.5 – 15.5 (– 20) μm; clavate, sometimes sphaeropedunculate or obpyriform, apically obtuse, repent with ascending tips or erect, often irregularly oriented, individual or in small to large fascicules; thin-walled, with brownish yellow parietal pigments. Clamp connections present.

Distribution and ecology.

Known only from Sardinia ( Italy); possibly an exclusively Mediterranean species.

Additional material studied.

Italy • Sardinia, near Olbia, Pittulongu , 11 Jan 2008, M. Contu 11. I. 2008 ( AQUI) .

Notes.

Two collections representing the type of D. pusillum and other authentic material were included in the study by Sánchez-García et al. (2021). The species was not collected by the authors of this study. It has amyloid spores and belongs to D. subgenus Amylospora , section Atrobrunnea . It forms a well-supported clade with D. obscurum , D. clavicystis and an unclarified Dermoloma species (Fig. 2 ; for morphological differences see notes under D. obscurum ). The most similar species is probably D. vestigium , due to its very small basidiomata and similar spores. They differ by narrower, attenuated and flexuous marginal cells and shorter caulocystidia in the latter species.

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 47. Dermoloma pusillum (AQUI 30. XII. 2006, holotype), 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.