Coprinellus pakistanicus Usman & Khalid

Hussain, Shah, Usman, Muhammad, Afshan, Najam-ul-Sehar, Ahmad, Habib, Khan, Junaid & Khalid, Abdul Nasir, 2018, The genus Coprinellus (Basidiomycota; Agaricales) in Pakistan with the description of four new species, MycoKeys 39, pp. 41-61 : 46-47

Coprinellus pakistanicus Usman & Khalid sp. nov. Figures 2and 6

Diagnosis.

The distinguishing features of Coprinellus pakistanicus are: light yellowish-green to greyish-yellow pileus, surface smooth with sub-membranous context, basidiospores 8.5-11.5 × 6.5-8.0 × 5.5-6.5 µm, on average 10 × 7.4 × 6.2 µm, in face view broadly ellipsoid, obovoid to phaseoliform, in side view ovoid, ellipsoid to obovoid, base not truncate, apiculus visible in side view, germ-pore central.

Type.

PAKISTAN: Punjab, Pabbi Forest Park, 286 m alt., 11 Aug 2016, M. Usman and Abdul N. Khalid, MU37 (Holotype LAH35323); GenBank accession ITS: MH366736.

Etymology.

The specific epithet “pakistanicus” refers to the holotype locality of this species.

Macroscopic characters.

Pileus 25-35 mm diam, convex to plan, with depressed centre, light yellow green (2.5GY 8/6) to greyish-greenish-yellow (7.5Y 7/4); surface smooth with sparsely pulverulent to granulose, deeply plicate from centre towards margin; centre depressed to slightly papillate, orange yellow (7.5YR 6/8); context sub-membranous, light greyish (10Y 5/2). Lamellae free, crowded, regular, dark brown to blackish, with 0-2 series of lamellulae. Stipe 27-50 × 1 mm, central, hollow, smooth, white, with slightly bulbous base. Annulus and volva absent. Odour and taste not recorded.

Microscopic characters.

Basidiospores (7 –)8.5–11.5(– 12) × (6.0 –)6.5–8.0(– 8.5) × ( –5.0)5.5–6.5(– 7.0) µm, on average 10 × 7.4 × 6.2 µm, Q1 = 1.4, Q2 = 1.6, av. Q = 1.3; in face view, broadly ellipsoid, obovoid to phaseoliform, in side view, ovoid, ellipsoid to obovoid, base not truncate, apiculus slightly visible, germ-pore central, smooth, slightly thin-walled, dark brown to blackish in KOH. Basidia 13.5-32 × 8.5-12 µm, clavate to narrowly clavate, hyaline, smooth, 2- to 4-spored, sterigmata up to 4 µm in length. Cheilocystidia 42-75 × 14-25 µm, cylindrical to lageniform, hyaline with crystals usually at the apex of cystidium. Pleurocystidia absent. Pileipellis irregular epithelium, 3.5-7.5 µm diam., pale to hyaline in KOH. Pileocystidia 30-90 × 9-24 µm, lageniform to cylindrical with tapering neck and obtuse apex, pale to hyaline in KOH. Veil rounded to globose cells, 15-25 µm diam., slightly thick-walled, yellowish in KOH. Clamp connection present.

Habitat and distribution.

Scattered on moist soil, under trees of Acacia nilotica and A. modesta , so far only known from lowland northern Pakistan.

Additional specimens examined.

PAKISTAN. Punjab: Pabbi Forest Park, 286 m alt., 20 Aug 2016 & 2017, M. Usman, Abdul N. Khalid and A. Hameed, MU07, MU39 (LAH35324 and LAH35325).

Comments.

In phylogenetic analyses, Coprinellus pakistanicus forms Clade III, adjacent to the Sabulicola and Eurysporoid clades of Nagy et al. (2012) and morphologically would be placed in sect. Setulosi . The new species is compared with the following species of sect. Setulosi : Co. bisporus (J.E. Lange) Vilgalys, Hopple & Jacq. Johnson, Co. cinereopallidus L. Nagy, Házi, Papp & Vágvölgyi, Co. congregatus (Bull.) P. Karst., Co. pellucidus (P. Karst.) Redhead, Vilgalys & Moncalvo, Co. radicellus Házi, L. Nagy, Papp & Vágvölgyi and Co. sabulicola L. Nagy, Házi, Papp & Vágvölgyi.

In Co. bisporus , the pileus is small, up to 20 mm diam., ochre or pale brown; with dark red-brown basidiospores; cheilocysticdia subglobose, ovoid, ellipsoid to broadly utriform and smaller in size (24-40 × 16-23 µm) when compared to Co. pakistanicus ( Prydiuk 2010). In Co. cinereopallidus , basidiospores are larger 12.1 × 6.5 µm, ellipsoid to subamygdaloid, not lentiform ( Nagy et al. 2012). Similarly, Co. congregatus with pileus up to 20 mm in diam., cream-coloured, at centre ochre-brown to light brown, cheilocystidia subglobose, ovoid to ellipsoid, sometimes utriform, 22-50 × 15-36 µm in size ( Prydiuk 2010). Coprinellus pellucidus with substantially small pileus (7 mm diam.), basidiospores 9.25 × 4.75 µm, elongate-ellipsoid to cylindrical-ellipsoid, with subglobose cheilocystidia, 20-25 × 14-22 µm ( Prydiuk 2010). Pileus in Co. radicellus up to 10 mm diam., cream coloured to dark melleous-brown, expanding to convex applanate with uprolled margin, basidiospores on average 9.48 × 4.91 µm, reddish-brown, ellipsoid to subcylindrical, with globose to subglobose or clavate cheilocystidia, 9-20 × 8-14 µm in size ( Házi et al. 2011). Co. sabuilcola has concave, warm reddish-brown pileus, basidiospores on average 17.3 × 10.9 µm, cheilocystidia 17-32 × 12.5-27 µm, globose to vesiculose or broadly ellipsoid ( Nagy et al. 2012).