Aureoboletus rugosus N. K. Zeng, Xu Zhang, L. P. Tang & W. H. Zhang 2022, sp. nov.
Creators: name: Zhang, Xu
name: Tian, Run
name: Tang, Li-Ping
name: Liang, Zhi-Qun
name: Zhang, Wen-Hao
name: Jiang, Shuai
name: Wang, Cheng-Kai
name: Zeng, Nian-Kai
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Boletales
Boletaceae
Aureoboletus
Aureoboletus rugosus

description: Aureoboletus rugosus N.K. Zeng, Xu Zhang, L.P. Tang & W.H. Zhang, sp. nov. (Figs. 3E–I, 6)
MycoBank: MB841625
Etymology: — Latin “ rugosus ” refers to the wrinkled pileus surface of the new species.
Diagnosis: — Differs from other species of Aureoboletus by small basidiomata, reddish-brown, violet brown, distinctly wrinkled pileal surface, a pileal margin usually with white to subhyaline, gelatinized veil remnants when young, cylindrical basidiospores, and an intricate ixotrichoderm-type pileipellis.
Holotype: — CHINA. Yunnan Province: Jianchuan County, Shibao Mountain Scenic Spot, elev. 2,504 m, 12 September 2019, W. H. Zhang 164 (FHMU6509). GenBank accession number: 28 S = OK327022, ITS = OK327022, TEF1 = OK357260, RPB2 = OM 280448.
Description: —Basidiomata small-sized. Pileus 3.3–3.5 cm in diam., subhemispherical when young, then broadly convex to applanate; margin usually with white (1A1) to subhyaline, gelatinized veil remnants when young; surface strongly viscid or mucilaginous, brown (7C4) to reddish-brown (7E6), distinctly wrinkled; context 0.3 cm thick in the center of the pileus, white (2A1), unchanging in color when cut. Hymenophore poroid, slightly depressed around apex of stipe; pores 0.5–1 mm in diam., subround, pale yellow (4A2), unchanging in color when cut; tubes approximately 0.7 cm long, pale yellow (4A2), unchanging in color when cut. Stipe 6–7.5 × 0.5–0.7 cm, central, subcylindrical; surface yellowish brown (4A3), strongly viscid when young, with distinct longitudinal streaks; context white, unchanging in color when cut. Basal mycelium white. Odor indistinct.
Basidia 27–31 × 9–10 μm, clavate, thin- to slightly thick-walled (up to 1 μm thick), 4-spored, hyaline or yellowish in KOH; sterigmata 4–4.5 μm long. Basidiospores [150/3/3] 10–13(–14.5) × 4–6 μm, Q = (1.67–) 2–3(–3.25), Qm = 2.45 ± 0.31, cylindrical, moderately thick-walled (up to 1 μm), smooth, yellowish brown in KOH. Cheilocystidia 35–55 × 11–16 μm, fusoid-ventricose or subclavate, moderately thick-walled (up to 1 μm), yellowish-white or hyaline in KOH. Pleurocystidia 32–55 × 9–16 μm, fusoid-ventricose or subclavate, thin- to slightly thick-walled (up to 1 μm), yellowish-white or hyaline in KOH. Hymenophoral trama bilateral, composed of hyphae 4–8 μm wide, moderately thick-walled (up to 1 μm), yellowish in KOH. Pileipellis an intricate ixotrichoderm 150–250 μm thick, made up of hyphae 4–6 μm wide, moderately thick-walled (up to 1 μm), yellowish (1A2) in KOH; terminal cells 27–65 × 5–5.5 μm, narrowly clavate or subcylindrical, with obtuse apex. Pileal trama composed of hyphae 2–12 μm wide, thin- to slightly thick-walled (up to 0.5 μm), hyaline in KOH. Stipitipellis a hymeniderm approximately 250 μm thick, embedded in a gelatinized matrix, made up of hyphae 4–6.5 μm wide, thin-walled, yellowish (1A3) or hyaline in KOH; terminal cells 12–22 × 4–9 μm, clavate, with obtuse apex. Stipe trama made up of parallel hyphae 4–10 μm wide, moderately thickwalled (up to 1 μm), yellowish brown (3B8) in KOH. Clamp connections not observed in any tissue.
Habitat: — Solitary or scattered on the ground in forests dominated by fagaceous trees (Quercus spp.), mixed with Pinus yunnanensis Franch.
Known distribution: — Southwestern China (Yunnan Province).
Additional specimens examined: — CHINA, Yunnan Province: Jianchuan County, Shibao Mountain Scenic Spot, elev. 2,542 m, 12 September 2019, G. L. Zhang 078 (FHMU2766); same location and date, L. P. Tang1679 (FHMU6510).
Notes: Phylogenetically and morphologically, A. rugosus is closely related to
A. thibetanus (Fig. 2). However, A. thibetanus has a distinctly reticulate pileal surface, and outer surfaces of pleurocystidia covered with a 5–8 μm thick layer of a strongly refractive yellow substance (Yang et al. 2003). Moreover, the phylogenetic distance is 0.036 between our new species A. rugosus and its sister species A. thibetanus (Fig. 2), which also falls within the range of values of 0.012 to 0.42 for the inter-specific variation of Aureoboletus species.
Aureoboletus rugosus is also morphologically similar to Chinese species, A. glutinosus, A. griseorufescens Ming Zhang & T.H. Li (2019: 124), A. tenuis, and Japanese species, A. viscidipes (Hongo) G. Wu & Zhu L. Yang (2016: 53). However, A. glutinosus has a smaller pileus (1–2 cm in diam.), and narrower basidiospores (only up to 5 μm in width) (Zhang et al. 2019); A. griseorufescens has a context more or less greyish-red beneath the pileipellis and browner at the border line adjacent to tubes, gradually changing to greyish-red to greyish-rose when cut, shorter basidiospores [(8–)9–10.5(–11) × (4–)4.5–5(–5.5) μm], and a pileipellis composed of more or less inflated hyphae (12–19 μm wide) (Zhang et al. 2019); A. tenuis has a yellowish pileal context, and narrower basidiospores (only up to 5 μm wide) (Zhang et al. 2014); A. viscidipes has a smaller pileus (up to 2.5 cm in diam.), a pileal surface paler in color, and apical surfaces of cystidia covered with a 2 – 3 μm thick layer of a refractive pale yellow substance (Wu et al. 2016).
description: Published as part of Zhang, Xu, Tian, Run, Tang, Li-Ping, Liang, Zhi-Qun, Zhang, Wen-Hao, Jiang, Shuai, Wang, Cheng-Kai & Zeng, Nian-Kai, 2022, Morphological and phylogenetic evidence reveal three new species of Aureoboletus (Boletaceae, Boletales) from China, pp. 127-148 in Phytotaxa 567 (2) on pages 142-143, DOI: 10.11646/phytotaxa.567.2.2, http://zenodo.org/record/7141696