The genus Coprinellus (Basidiomycota; Agaricales) in Pakistan with the description of four new species Author Hussain, Shah Author Usman, Muhammad Author Afshan, Najam-ul-Sehar Author Ahmad, Habib Author Khan, Junaid Author Khalid, Abdul Nasir text MycoKeys 2018 39 41 61 http://dx.doi.org/10.3897/mycokeys.39.26743 journal article http://dx.doi.org/10.3897/mycokeys.39.26743 1314-4049-39-41 Coprinellus tenuis Hussain sp. nov. Figures 1 C-Dand 7 Diagnosis . The new species Coprinellus tenuis can be recognised by its thin and membranous pileus, surface glabrous and furred, deeply plicate towards margin; lamellae sinuate to uncinate; basidiospores 10.5-14.5 x 8.0-9.5 x 6.5-8.5 µm , in face view, broadly ellipsoid to ovoid, in side view, slightly pyriform to ellipsoid, usually with truncate base, apiculus mostly not visible, with eccentric germ-pore, 1.5-2 µm wide. Type . PAKISTAN: Khyber Pakhtunkhwa, Malakand, Qaldara, 430 m alt., solitary on leaf litter, 7 July 2014, S. Hussain, SHP10 (SWAT-SH-P10, holotype); GenBank accession ITS: MH753663. Etymology. "tenuis" (Latin) meaning thin, referring to the membranous pileus of the new species. Macroscopic characters. Pileus 15-20 mm diam, pulvinate to convex to plane, light greyish-brown (7.5YR 5/2) to light brown (5YR 6/4); surface glabrous, furred, deeply plicate from centre towards margin; centre truncately conical, moderate reddish-orange (10R 5/8) to greyish-reddish-orange (2.5YR 5/6); context membranous. Lamellae sinuate to uncinate, distant, with 0-2 series of lamelullae, light greyish-brown (7.5YR 5/2) to light brown (5YR 6/4), lamellae edge blackish and fimbriate to eroded. Stipe 40-60 x 1 mm, equal, cylindrical, surface scabrous, white, translucent, fragile, context hollow. Microscopic characters. Basidiospores (9.0 -)10.5-14.5(- 15.5) x (7.5 -)8.0-9.5(- 10.5) x (5.0 -)6.5-8.5(- 9.0) µm , on average 13.1 x 9.0 x 7.8 µm ; Q1 = 1.25-1.49, Q2 = 1.57-1.63, av. Q = 1.45; in face view, broadly ellipsoid to ovoid, in side view, slightly pyriform to ellipsoid, usually with truncate base, apiculus mostly not visible, germ-pore eccentric, 1.5-2 µm wide, wall 1.5 µm thick, dark brown to almost black. Basidia 22-24 x 9-12 µm , clavate, 2- to 4-spored, hyaline in KOH. Cheilocystidia 22-30 x 19-28 µm , rounded to globose, abundant, hyaline. Pleurocystidia absent. Pileocystidia 78-94 x 10-12 µm , lageniform to cylindrical with rounded apex, elongated rod shape neck with rounded enlarged base, hyaline in KOH. Caulocystidia 50-67 x 9-11 µm , narrowly clavate to clavate, with rounded to obtuse apex, cylindrical base. Veil comprised of rounded to subglobose cells, arranged in short chain, thick-walled with encrusted walls, dark brown, with terminal cell 17-23 x 12-15 µm . Habitat and distribution. Scattered on leaf litter under Acacia modesta , so far only known from lowland northern Pakistan. Additional specimens examined. PAKISTAN. Khyber Pakhtunkhwa: Malakand, Qaldara, on leaf litter under Acacia modesta , 10 July 2014, S. Hussain, SH10 (SWAT SH-10). Comments. Coprinellus tenuis with thin membranous pileus, shows similarities with Co. curtus . Both these species can be differentiated on (i) pileus morphology (ii) basidiospore shape and (iii) habitat. Pileus is deeply plicate in both these species, in Co. tenuis pileus is glabrous and furred; however, there is no furcation in the pileus of Co. curtus . Spores in Co. curtus are substantially smaller (8.0-10.0 x 5.5-7.0 µm ), ellipsoid to ovoid in face view, narrowly ellipsoid or phaseoliform in side view, apiculus often not visible, with a distinct central to slightly eccentric germ-pore, not truncate. Basidiospores in Co. tenuis are larger (10.5-14.5 x 8.0-9.5 x 6.5-8.5 µm ), in face view broadly ellipsoid to ovoid, in side view slightly pyriform to ellipsoid, usually with truncate base, apiculus mostly not visible, with eccentric germ-pore of 1.5-2 µm diam. Coprinellus curtus has a substrate preference and is most commonly collected from herbivores' dung as opposed to Co. tenuis basidioma on leaf litter ( Ulje and Bas 1991 ).