Conocybe pruinosa Morera, Lupo & Kuhar, 2024

Morera, Guillermo, Kuhar, Francisco, Rodriguez, Luisina, Carrera, Ignacio, Davyt, Danilo & Rizzo, Sandra Lupo, 2024, A new species and new records of dung-associated bolbitiaceous fungi (Bolbitiaceae, Basidiomycota) from Uruguay, Phytotaxa 678 (2), pp. 109-124 : 114-117

Conocybe pruinosa Morera, Lupo & Kuhar , sp. nov. ( Figs. 3 , 4 )

MycoBank:—854492

Etymology:—The epithet refers to the distinctive waxy or “pruinose” appearance of the pileus surface.

Diagnosis:—The species is morphologically distinguishable by its pruinose pileus surface, large basidiospores (11.4–19.8 × 6.2–12.8 µm) and absence of lecythiform caulocystidia.

Holotype:— URUGUAY. Maldonado, Sierra de las Ánimas , on cow dung, (34° 48’ 33" S, 58° 15’ 31" W, 209 m a.s.l.), 23 March 2021, G. Morera & S. Lupo ( MVHC 5749 ).

Description:— Pileus 0.5–2.3 × 0.5–1.5 cm, hemispherical, almost parabolic or bell-shaped to conical in lateral view, pale brown (5C6; Brownish Orange) to homogeneous ocher (6D7; Light Brown), hygrophanous, with pruinose surface shiny to more opaque, generally dry, translucent-striate. Margin slightly incurved, entire, crenate or wavy, distinctively pale or concolorous to darker brown (8F8; Dark Brown). Lamellae subdistant to proximal, adnexed to subfree, chestnut and waxy face usually concolorous with pileus; the edge of the lamella appears smooth and concolorous with the surface. Stipe 1–13 × 0.2–0.5 cm, somewhat broadened at the base, without basal tomentum, pale (5A2; Orange white) to yellowish brown (5B6; Greyish Orange), rather ochraceous where cut (5A5; Light Orange), surface smooth to finely pubescent and striate, sometimes showing deposits of ferruginous spores, fibrous and fragile. Ring absent. Context 0.2 cm, concolorous with the pileus to slightly darker (5D7; Golden Brown). No bluing reaction. Smell farinaceous. Spore print ferruginous brown.

Basidiospores (11.4) 12.2–19.2 (19.8) × 6.2–11.3 (12.8) µm, Q =1.65–2, Qm=1.85, subangular in frontal view and oblong with one side slightly flattened in lateral view (amygdaliform), smooth, pigmented, yellowish brown to ochre (in KOH), 1 µm thick wall, with a conspicuous central germinal pore. Basidia 14–28 × 8–16 µm, with 4 sterigmata, globose, subglobose to broadly clavate, hyaline. Cheilocystidia 9.9–24.7 × 5.3–10.6 µm, leptocystidia lecythiform, neck, 0–4.5 × 1.1–4.3 µm and capitate apex, 2–5.1 µm. Pleurocystidia not observed. Hymenophoral trama of intertwined to subparallel hyphae, 1–1.5 µm in diameter. Pileipellis as a hymeniform cystodermis, with pyriform, ampuliform, clavate, or more unusual, irregular elements, 20–53.3 × 12.2–36 µm, interspersed with cylindrical pileocystidia, 13.1– 54.8 × 3.3–11.3 µm and hairs, viz., filiform pileocystidia, 30–140 × 2–3.2 µm. Pileus trama consisting of a layer of pigmented hyphae and sphaerocysts. Stipe hyphae 5.8–20 µm, parallel, thick-walled, yellowish brown. Caulocystidia of different types, some consisting of clustered or isolated hairs 50–140 × 1–2 µm and spheroid elements (13.6 × 12.5 µm), occasionally with a capitate apex, others shaped as irregularly ventricose elements (10.3–22.4 × 4.7–6.6 µm) and others cylindrical to subutriform (20–32.6 × 2.7–4.6 µm), sometimes branched.

Distribution and habitat:—gregariously on cow and horse dung (up to 11 specimens). Described from Uruguay, probably present in Pakistan and USA according to the occurrence of identical DNA sequences.

Additional specimens examined:— URUGUAY. Maldonado, Sierra de las Ánimas, on cow dung (34°48′33″S, 58°15′31″W elev. 209 m a.s.l.), 23 March 2021, G. Morera & S. Lupo (MVHC 5748, MVHC 5755 and MVHC 5756); Lavalleja, surroundings of Salto del Penitente, Eucalyptu s sp. plantation on cow and horse dung (34° 23’ 34.1808″S, 55° 2’ 47.8206"W, elev. 311 m a.s.l.), 22 May 2022, G. Morera & S. Lupo (MVHC 5750, MVHC 5751, MVHC 5752, MVHC 5753, MVHC 5754, MVHC 5759, MVHC 5760, MVHC 5761). Conocybe magnispora (Murrill) Singer (1950 a: 135) (WU-MYC0041435), Conocybe pubescens (Gillet) Kuhner (1935: 85) (WU-MYC0020759), Conocybe singeriana Hauskn. (1996: 256) (WU-MYC0022129), Conocybe merdaria Arnolds & Hauskn. (2003: 239) (WU-MYC0022987) and Conocybe watlingii Hausknecht (1996: 193) (WU-MYC0021238).

Figures

FIGURE 3. Macro and micro-morphological pictures of Conocybe pruinosa.A–C. Basidiomes (MVHC 5749:A, MVHC 5748: B, MVHC 5751: C), D. Pileipelis (MVHC 5750), E. Pileocystidia (MVHC 5750), F. Basidia (MVHC 5751), G. Basidiospores (MVHC 5749), H–I. Caulocystidia (MVHC 5761), J. Cheilocystida (MVHC 5748). Scale bars: (A–C) 1 cm, (D–J) 10 µm. Photos by: G. Morera.

FIGURE 4. Micromorphological characters of Conocybe pruinosa. A. Basidiospores (MVHC 5749), B. Basidia (MVHC 5751), C. Cheilocystida (MVHC 5751), D. Stipitipellis elements (MVHC 5761), E. Pileipellis elements (MVHC 5750). Scale bars: 10 µm. Drawings by G. Morera.