Entoloma arenicola Karstedt & Capelari

Karstedt, Fernanda, Bergemann, Sarah E., Gates, Genevieve, Ratkowsky, David, Cunha, Kelmer Martins & Capelari, Marina, 2024, Species of Entoloma (Entolomataceae) with cuboidal basidiospores from Brazil, Phytotaxa 654 (1), pp. 1-76 : 22-24

Entoloma arenicola Karstedt & Capelari sp. nov.

Figs. 6 , 10g –i , 35a–b

MB 838584

Etymology:— Arenicola refers to the sandy soil where the specimens were collected; arenosus (Latin), sandy.

Diagnosis:— E. arenicolor is characterised by the combination of its lilac to vinaceous pileus, cuboidal basidiospores, cheilocystidia that vary from cylindrical, cylindro-clavate to cylindro-strangulate and a pileipellis as a cutis in transition to a trichoderm.

Type:— BRAZIL. Pará: Caxiuanã, Caxiuanã National Forest , Ferreira Penha Station , in a plot of the EsecaFlor project, 10 February 2011, F. Karstedt et al. FK1811 (Holotype, SP).

Description:— Pileus 8–33 mm diam., conical, conico-convex, convex or applanate with conical center or umbonate with papilla, opaque, pale lilac, greyish pale lilac, greyish lilac, pinkish pale lilac, vinaceous pink or red-purple, with a darker center, slightly hygrophanous, surface radially or concentrically squamulose-fibrillose or fibrillose-squamulose, sometimes fibrillose at center and slightly fibrillose-squamulose, fibrillose or adpressed-fibrillose at margin, margin smooth or irregular. Pileus context thin and white. Lamellae sinuate, ventricose (<6.5 mm at deepest part), white, beige, light brownish beige or light pinkish beige, close, with 2–3 tiers of lamellulae, margin entire, concolorous with faces or sometimes brownish with age. Stipe 25–62 × 1–4 mm, cylindrical or attenuated upwards, centrally attached or slightly eccentric, white, beige, light greyish lilac or pale vinaceous, usually with pale lilac fibrils, longitudinally striate and twisted, slightly fibrillose, fibrous, fistulose, inner part of stem yellowish or brownish yellow, with white basal tomentum, rhizoids white. Stipe context white. Odor and taste not observed. Spore print not observed.

Basidiospores cuboidal, with an obvious hilar appendix, 7.5–10 × 6.2–8.7(–10) µm [xm = 8.64 (± 0.87) × 8.28 (± 0.84) µm, Q = 1–1.28, Qm = 1.05 (± 0.07), n = 104/7], thin-walled. Basidia clavate or cylindro-clavate, 31– 56(–63) × 11–15 µm (n = 59/5), hyaline, thin-walled, 4-sterigmate. Cheilocystidia along the entire lamellar margin, cylindrical, cylindro-strangulate, cylindro-clavate, clavate, irregular or hyphoid, sometimes branched, sometimes slightly collapsed, (28–)50–112 × 5–19 µm (n = 61/6), hyaline or slightly straw yellow, thin-walled. Pleurocystidia and pseudocystidia absent. Lamellar trama formed by subparallel hyphae, cylindrical or inflated, sometimes branched, 3.7–18 µm diam. (n = 89/6), hyaline, thin-walled, rarely septate, sub-hymenium with branched hyphae. Pileitrama composed of radially entangled, cylindrical, broadly cylindrical or slightly fusoid hyphae, 3.7–22 (–27) µm diam. (n = 57/5), hyaline, thin-walled, septate. Pileipellis a cutis in transition to a trichoderm, subcutis a layer of prostrate and slightly entangled, cylindrical hyphae, 3.7–11.2 µm diam. (n = 53/5), hyaline or straw yellow, thin-walled, supracutis composed of prostrate or anticlinal hyphae, usually forming groups, not covering the entire surface, cylindrical, broadly cylindrical, cylindro-clavate or cylindro-fusoid, 34–125 × 10–19 µm (n = 61/6), hyaline or with brown intracellular pigment, sometimes with yellow parietal pigment (in KOH), thin-walled. Stipitipellis a cutis, with cylindrical hyphae, 3.7–8.7 µm diam. (n = 41/3), hyaline or straw yellow, thin-walled, septate. Caulocystidia dispersed, solitary or in small groups, anticlinal, clavate or cylindro-clavate, sometimes septate, 25–50 × 5–7.5 µm (n = 14/2), hyaline or straw yellow, thin-walled. Clamp connections present. Refractive hyphae present.

Habitat:—Solitary, dispersed or gregarious, in sandy soil with litter, in the Amazon Forest and Atlantic Forest.

Distribution:—Occurs in the states of Pará and Rio Grande do Norte, Brazil.

Additional material examined:— BRAZIL. Pará: Caxiuanã, Caxiuanã National Forest, Ferreira Penha Station , in a plot of the EsecaFlor project, 10 February 2011, F. Karstedt et al. FK1812 (paratype, SP), FK1816 (paratype, SP) . Rio Grande do Norte: Natal, Dunas de Natal State Park, Perobinha Trail , 17 July 2010, N. Menolli Jr. NMJ194 ( SP), NMJ195 ( SP); Geology Trail, 6 July 2011, M. Capelari et al. 4601 ( SP); 21 July 2011, F. Karstedt & M.A. Sulzbacher FK2089 ( UFRN) .

Comments:—The materials collected in Pará and Rio Grande do Norte are not identical. They vary in color of the pileus, the first being more vinaceous and the second more lilaceous. The basidiospores are slightly smaller [7.99 (± 0.60) × 7.54 (± 0.45) µm] in the samples from Pará and larger [9.24 (± 0.67) × 8.92 (± 0.56) µm] in samples from Rio Grande do Norte. There are also variations regarding the pigmentation of the terminal hyphae of the pileipellis, with the materials from Pará showing yellow parietal pigment whereas those from Rio Grande do Norte are hyaline or have brown intracellular pigment. These variations could be considered relevant for separating the collections into two distinct species; however, no molecular evidence was found to support the segregation of the collections into two species ( Fig. 3 ). Genetic distance tests carried out with the nLSU, mtSSU, rpb2 and tef1 genes also indicated great similarity between the collections sampled in Rio Grande do Norte (FK2089, M. Capelari et al. 4601, NMJ195) and the collection sampled in Pará (FK1811). The species that most resembles Entoloma arenicola is Entoloma acutoconicum but that species differs in its brown to reddish brown pileus covered by vinaceous brown to purple fibrils. Furthermore, E. acutoconicum has a pileipellis composed of a cutis usually with straw yellow or hyaline intracellular pigment, whereas E. arenicolor has prostrate or sub-erect hyphae with intracellular encrusted brown pigment.

Figures

FIGURE 3. Phylogenetic reconstruction of the species of Entolomataceae with cuboid basidiospores and related species based on the combined genes (nLSU, mtSSU, rpb2 and tef1). Bootstrap values (> 70%) from the maximum likelihood analysis are indicated above the branches. The species studied here are shown in boldface. AU: Australia, AT: Austria, BZ: Belize, BR: Brazil, CN: China, GY: Guyana, IN: India, MY: Malaysia, NZ: New Zealand, PG: Papua New Guinea, PR: Puerto Rico, RE: La Reunion, UK: Russia, SC: Seychelles, US: United States, VN: Vietnam. Dashed vertical line: have similarity in the morphology but no molecular support.

FIGURE 6. Entoloma arenicola: a–c. basidiospores: a. FK2089; b. NMJ194; c. FK1811; d. basidia (FK1811); e–f. cheilocystidia: e. FK1811; f. FK2089; g. pileipellis (FK1811). Scales: a–f: 10 µm, g: 20 µm.

FIGURE 10. Microphotography of basidiospores in electron microscopy: a–c. Entoloma acutipallidum (11RMT078); d–f. E. amazonicum (FK1815); g–i. E. arenicola (FK1811); j–m. E. capes (FK2096), n–p. E. caxiuanense (FK1871). Scale: 5 µm.

FIGURE 35. Basidiomas: a–b. Entoloma arenicola: a. FK1811; b. FK2089; c–e. E. voltavelhense: c. FK1694; d–e. FK2118; f–g. E. vinososquamulosum (FK1745). Photos: F. Karstedt. Scale: 1 cm.