Mallocybe pakistanica Saba & Khalid, 2023

Saba, Malka, Khalid, Abdul Nasir & Sarwar, Samina, 2023, New species of Mallocybe (Agaricales, Inocybaceae) from Pakistan, based on morphological, MycoKeys 99, pp. 171-186 : 171

Mallocybe pakistanica Saba & Khalid sp. nov.

Figs 2 , 3

Diagnosis.

Most similar to Mallocybe myriadophylla described from north-western Europe, but differs by the absence of a crowded lamellae, different pileal colouration and somewhat larger basidiospores. Phylogenetically separated from other species of Mallocybe due to unique ITS and LSU sequences.

Types

. Holotype: PAKISTAN, Prov. Khyber Pakhtunkhwa, Mansehra, Chattar Plain, under Pinus wallichiana A. B. Jacks., 22 September 2013, leg. M. Saba & A.N. Khalid; MSM#0061 (ISL-F002); GenBank accession nos. OK360951 (ITS), OK392118 (nrLSU). Paratype: Pakistan, Prov. Khyber Pakhtunkhwa, Mansehra, Chattar Plain, under Pinus wallichiana , 2 September 2015, leg. M. Saba & A.N. Khalid; MSM#00132 (ISL-F003); GenBank accession nos. OK360952 (ITS), OK392119 (nrLSU). Sep 2021, MSM#0201, (ISL-F004); GenBank accession nos. OK360953 (ITS), OK392120 (nrLSU).

Etymology.

Referring to the country where it was discovered.

Description.

Pileus 19-24 mm diam., plane; margin deflexed in mature basidiomata, not splitting; surface dull, scaly, floccose, light brown (7.5YR6/4) or pale yellowish-brown (10YR7/4). Lamellae adnexed, subdistant, margin entire, regular, concolorous, moderate brown (7.5YR3/4) or strong brown (5YR4/6), one to two tiers of lamellulae or variable. Stipe 31-35 mm, central, equal, floccose, pale yellowish-brown (5YR8/8) or pale yellow (2.5Y9/4), cortina zone not seen; annulus absent. Context pale brown, tough, up to 2 mm thick. Odour not distinctive, somewhat fungoid. Taste not recorded.

Basidiospores 7.4-13.2 × 5-6.6 µm [x = 10.8 × 5.9 µm, Q = 1.3-2.2], ellipsoid, ovoid, thin-walled, pale brown with yellowish contents in KOH. Basidia with yellowish necropigment, 25.7-36 × 6.8-10.3 µm, clavate, usually four-spored, thin-walled, hyaline in KOH; sterigmata 3.6-5.3 µm. Pleurocystidia absent. Cheilocystidia 14.8-31 × 9-15.8 µm, cylindrical, hyaline, in chains. Caulocystidia 38-43.6 × 5.5-7.0 µm, hyphal, yellowish-brown in KOH with clamp connections at base, thin-walled, abundant at the apex of stipe. Pileipellis hyphae cylindrical, pale brown in mass in KOH, 5-12 µm, thin-walled. Stipitipellis hyphae cylindrical, 6-10 µm, yellowish or olivaceous in KOH. All structures inamyloid. Clamp connections present.

Habitat.

Occurring in September, solitary, scattered on the forest floor in stands of Pinus wallichiana ( Pinaceae ).

Known distribution.

Currently known from Western Himalayas, Pakistan.

Notes.

Mallocybe pakistanica can be characterised by small to medium-sized basidiomata, pale yellowish-brown or light brown pileus, ellipsoid basidiospores and catenate cheilocystidia (in chains). Based on the phylogenetic analysis (Fig. 1 ), conducted using the combined dataset ITS+LSU, indicate that the closet taxon is Mallocybe sp. BK 6-June-97-24 (MN178541) which is not yet published (Personal communications with P. Brandon Matheny). Mallocybe myriadophylla (Vauras & E. Larss.) Matheny & Esteve-Rav. is another closely related taxon which can be differentiated by different colouration of the pileus (when young pale brownish-grey, then grey brown, pale brown to brown, centre often darkest yellow-brown), presence of crowded lamellae and somewhat smaller phaseoliform basidiospores ((7.3-) 7.9-9.6 (-10.6) × (4.5-) 4.7-5.5 (-5.7) μm) ( Vauras and Larsson 2011).

Another closely-related species in the adjacent clade is Mallocybe tomentosula Matheny & Esteve-Rav., in Matheny, Hobbs & Esteve-Raventós which morphologically can be differentiated by the presence of a superior cortinate ring-zone, slightly smaller size of basidiospores and by its occurrence in eastern North America. Both ML and MP phylogenetic analyses also clearly support the identity of this new taxon as independent monophyletic clade.

Figures

Figure 1. Phylogeny of Mallocybe pakistanica, M. pinicola and related taxa produced from Maximum Likelihood (ML) inference using combined dataset of ITS and nrLSU sequences. Numbers on branches are ML / MP bootstrap values (only ≥ 70). New sequences reported in this study are blue coloured.

Figure 2. Holotypes A Mallocybe pakistanica (MSM # 0061) B Mallocybe pinicola (MSM # 0060). Scale bars: 10 mm (A, B).

Figure 3. Mallocybe pakistanica (holotype) A basidia B basidiospores C cheilocystidia D pileipellis E caulocystidia. Scale bars: 10 µm (A); 5 µm (B); 15 µm (C); 25 µm (D); 15 µm (E).