Coprinellus punjabensis Usman & Khalid sp. nov.

Index Fungorum number: IF 557381; MycoBank number: MB 557381; Facesoffungi number: FoF 07848; Fig. 1

Etymology – Named after Punjab Province, where this fungus was collected.

Holotype – LAH35321

The most important features of Coprinellus punjabensis: Pileus cylindrical to campanulate, white greyish, plicate from center to margins. Basidiospores 7.3–9×4.3–5.2 μm ellipsoid to amygdaliform, brown to blackish, germ pore central up to 1.2 μm, with truncate base. Veil elements globose to sub globose hyaline cells up to 45 μm. Macroscopic characters: Pileus 5−12 mm diam., cylindrical when young campanulate at maturity, white to light greyish (2.5Y 7/4), surface pruinose, plicate toward margin, edges striate to plicate. Lamellae sinuate to uncinate, distant with 1–3 lamellulae, dark greyish-brown. Stipe 25−40 μm in length, equal, central, light greyish and white near base, hollow, surface pruinose to pulverulent. Annulus absent. Odour and taste not recorded. Microscopic characters: Basidiospores (7–)7.3–9(–9.3) × (4–)4.3–5.2(–5.6) μm, (x̅=8 × 4.8 μm, n = 50), Q = 1.68; in face view, ellipsoid, in side view, amygdaliform, dark brown to blackish (5YR 3/1), in KOH, smooth, thick-walled, apex truncate, germ-pore central, up to 1.2 μm wide. Basidia 20−30×5.8−8.4 μm, cylindrical to clavate, hyaline with 2−4 strigmata up to 6 μm. Cheilocystidia and pleurocystidia absent. Pileipellis consist of irregular epithelium, arranged by globose to sub-globose cells, 8−30×10−25 μm, hyaline and smooth. Stipitipellis 3–10 μm diam., regular, septate and clamp connections not observed. Veil elements up to 45 μm, globose to sub-globose, smooth and hyaline.

Habitat and distribution – Solitary to gregarious on moist soil, rich in leaf litter under trees of Acacia modesta Wall.

Material examined – PAKISTAN, Punjab, Pabbi Forest Park, (32°49′52.94″ N 73°50′12.04″ E,) 286 msl, 11 August 2016, M. Usman and A.N. Khalid, MU30 (LAH35321, holotype). PAKISTAN, Punjab, Pabbi Forest Park, (32°49′51.30″N 73°50′16.24″ E,) 288 msl, 26 July 2017, M. Usman and A. Hameed, MU58 (LAH36392).

GenBank numbers – ITS=MT180990, MT180991.

Notes – Closely related species, including Coprinellus disseminatisimilis Hussain mostly resemble C. punjabensis (Fig. 1) in having cylindrical to campanulate pileus, length of cylindrical stipe 20–40 μm, absence of annulus, ellipsoid to amygdamliform dark brownish basidiospores and hyaline cylindrical to clavate basidia (Hussain et al. 2018). Coprinellus disseminatus also resemble with our taxon in having whitish grey cylindrical stipe, lamellulae 0–3, globose to subglobose veil elements up to 40 μm (Uljé 2005). However, C. punjabensis differs from C. disseminatisimilis in smaller size of white greyish pileus up to 12 mm diam., lamellulae 0–3, pileipellis irregular epithelium, veil elements hyaline globose to sub-globose up to 45 μm while C. disseminatisimilis has larger greyish-brown to greyish-yellowish-brown pileus (15–20 μm diam.), lamellulae 0–2, pileipellis light brown to hyaline loosely euhymenoderm, veil elements greyish brown up to 40 μm (Hussian et al. 2018). Coprinellus disseminates also differs from C. punjabensis in having larger pale-brown to yellow–brown, sometime almost white conical to convex pileus (up to 20 μm diam.), ovoid to obconical red dark brown basidiospores (Uljé 2005). Furthermore, phylogenetic analyses indicate that C. punjabensis forms a basal lineage in the clade with 100% MLBS support (Fig. 2). To provide the recommendation to justify our new species, we follow Hussain et al. (2018). Comparison of 625 nucleotides of the ITS sequences between C. punjabensis (MT180990) and C. disseminatisimilis (MH753670) reveals 32 substitutions and 6 deletions in our taxon (6.08% nucleotide difference) while comparison of 643 nucleotides of ITS sequences between C. punjabensis (MT180990) and C. disseminates (JN159560) reveals 23 substitutions and 27 deletions in our taxon (7.77% nucleotide differences), which we believe should be sufficient to delineate our new species.

Figure 1 – Coprinellus punjabensis (LAH35321, holotype). a Fresh basidiomata. b Basidiospores. c–e Veil elements. f Hymenium having immature and mature basidia. g A mature basidium with sharp strigmata. h Pileipellis. Microscopic structures were captured after stain with Congo red. Scale bars: a=10 mm, b=10 µm, c–g=20 µm, h=15 µm

Figure 2 – Phylogram generated from maximum likelihood analysis based on ITS sequence data representing Coprinellus punjabensis (MT180990) and related species. Related sequences are taken from Hussain et al. (2018). Fifty-five sequences are included in the analysis which comprise 708 characters after alignement. Psathyrella candolleana (KJ917666) is used as the outgroup taxon. The best RAxML tree with a final likelihood values of − 4869.810366 is presented. The matrix had 351 distinct alignment patterns, with 15.82% undetermined characters or gaps. Estimated base frequencies were as follows: A=0.233377, C=0.241159, G=0.233394, T=0.292070; substitution rates AC=1.849754, AG=2.784571, AT=1.813146, CG=1.135142, CT=1.135142, GT=1.000000; gamma distribution shape parameter α=0.294349. Bootstrap values for maximum likelihood (MLBS) equal to or greater than 75%. The newly generated sequence is in blue bold