Gymnopilus dunensis H. Bashir, S. Jabeen & Khalid, 2020

Bashir, Hira, Jabeen, Sana, Bashir, Humaira & Khalid, Abdul Nasir, 2020, Gymnopilus dunensis, a new species from Punjab province, Pakistan, Phytotaxa 428 (1), pp. 51-59 : 52-57

Gymnopilus dunensis H. Bashir, S. Jabeen & Khalid sp. nov. Figure 2 & 3

MycoBank no.: MB 828283

Etymology: — The specific epithet refers to the ‘sand dunes’ from where the specimens were collected.

Diagnosis:—Radicating growth habit as stipe base has narrow extension penetrating the Eucalyptus wood, basidiospores 9.7 × 5.8 µm, verrucose, clamps present on all hyphae.

Description: —Pileus 9–35 mm diam, height 38–56 mm, broadly umbonate becoming broadly convex at maturity, light yellow (5Y8/8) when young to yellowish brown (10YR7/8), lighter towards margin with appressed greyish scales scattered thoroughly, pileus becoming dark brown at maturity with irregularly incised margin, margin orange-brown colored and darker (2.5YR5/12) than surface, sometimes appendiculate with few velar remnants at young stage. Context 1–5 mm broad, creamy white (10Y9/2), solid, color unchanging upon cutting. Lamellae 3–5 mm broad, yellowish brown (10YR7/8), adnexed, slightly wavy to serrate margins, sub-distant to crowded, concolorous, lamellulae present. Stipe 32–53 mm long, 5–7 mm wide at apex, 2.5 mm at base, slightly radicating with narrow base, fibrillose, slightly appressed squamules, dull surface, white from the top and rusty from center to the base, color changing to yellowish brown with greenish tinge towards base upon bruising, partially hollow, context concolorous. Annulus membranous dark reddish brown (5YR1/4), present in young basidiomata, ring zone observed at maturity.

Basidiospores [60/3/3], (8.0) 8.5–10.7 (11.2) × (4.5) 4.9–6.6 (6.8) µm, Q = 1.6–1.8, avQ = 1.7, broadly ellipsoid, thick-walled, verrucose with small to medium warts, with slight suprahilar depression, dextrinoid, germ pore absent, dark brown, one or more guttules present. Basidia (22.9) 24.9–29.4 (31.5) × (7.8) 8.5–9.7 (9.9) µm, clavate, hyaline in KOH, oil-like droplets present, with or without basal clamp. Cheilocystidia (23.3) 23.7–27.9 (28.4) × (5) 5.4–6.7 (8.7) µm, lecythiform to narrowly utriform, capitate to sub-capitate, hyaline, oil droplets present, thin-walled, with well-defined basal clamp. Pleurocystidia (25.4) 27.3–31.1 (35.1) × (5) 5.4–6.7 (8.7) µm, fusoid-ventricose to narrowly utriform, with or without basal clamp, thin-walled, hyaline, oil droplets present. Pileipellis a cutis of filamentous hyphae with some inflated cells, 5–20 µm diam, with very light rusty brown plasmatic pigment, thin-walled, clamps present. Pileocystidia absent. Stipitipellis filamentous hyphae 3–7.5 µm diam, some inflated hyphae observed with constrictions at septa, thin-walled, light rusty brown in KOH, clamp connections present.

Habit and habitat:—Gregarious in small groups on sandy soil.

Holotype:— PAKISTAN. Punjab province, Bahawalpur district, Lal Suhanra National Park, Cholistan desert, on wood of Eucalyptus camaldulensis , 128 m a.s.l., 30August 2016, Hira Bashir & Muhammad Usman L-04 (LAH35874!). GenBank no.: MK088247

Additional specimens examined:— PAKISTAN. Punjab province, Bahawalpur district, Lal Suhanra National Park, Cholistan desert, on wood of Eucalyptus camaldulensis , 128 m a.s.l., 30 August 2016, Hira Bashir & Muhammad Usman L-90 (LAH35875!). GenBank no.: MK088248; Punjab province, Narowal district, Narowal, 234 m a.s.l., 13 August 2017, Humaira Bashir Hum-46 (LAH35876!). GenBank no.: MK088249.

Comments:—The phylogenetic data indicated that the closest species to G. dunensis is nested in the G. purpureosquamulosus complex, with nucleotide differences at six positions from the type sequence (EU401713). In addition to six differences, three polymorphic positions were also observed within three collections of our Pakistani taxon ( Table 1). The Indian taxon (KU302712) has nucleotide differences at 11 positions from G. dunensis excluding polymorphic positions and seven nucleotide differences from the type of G. purpureosquamulosus . The Indian taxon is positioned basal to the G. purpureosquamulosus complex and is closer to G. cyanopalmicola (EU401711) forming an isolated branch from all other sequences in the complex. So, it can be considered as a separate taxon as its sequence is not identical to the type of G. purpureosquamulosus . The position of G. dunensis in the tree is helping to solve or at least to realize that G. purpuresoquamulosus is not a single species but a complex of species.

Morphologically, the type specimen of G. purpureosquamulosus (from Zimbabwe) has a pileus with a central depression and a surface covered with reddish violet squamules, in contrast, G. dunensis has an umbonate pileus especially when young and the surface has greyish squamules. The lamellae are adnate-decurrent to decurrent in G. purpureosquamulosus but adnexed in G. dunensis . The stipe of G. dunensis can be distinguishable from other species of the genus Gymnopilus by having a radicating shape. In addition, pleurocystidia were not observed in the type specimen of G. purpureosquamulosus but fusoid-ventricose to narrowly utriform cystidia were abundantly in G. dunensis . All of the taxa in the clade where G. dunensis is clustered possess erect reddish to purplish colored squamules on the pileus surface (Guzmán-Dávalos et al. 2008) while this feature is absent in our species.

Figures

FIGURE 2. Macromorphological characters of G. dunensis sp. nov. A–B = LAH35874 (Holotype); C = LAH35875; D–E = LAH35876. Photos by Hira Bashir. Bars:A = 0.7 cm, B = 0.87 cm, C = 0.7 cm, D = 1.3 cm, E = 1.2 cm

FIGURE 3. Micromorphological characters of G. dunensis sp. nov. (LAH35874) A = Basidiospores, B = Basidia, C = Cheilocystidia, D = Pleurocystidia, E = Pileipellis elements, F = Stipitipellis elements. Drawings by Sana Jabeen. Bars:A = 0.6 µm, B = 0.8 µm, C = 0.6 µm, D = 0.8 µm, E = 1.3 µm, F = 0.7 µm