Hyphodontia yunnanensis C.L. Zhao & Y.C. Dai, sp. nov.

Index Fungorum number: IF 558551; MycoBank number: MB 558551; Facesoffungi number: FoF 09971; Figs. 1, 2

Etymology – “yunnanensis” refers to collecting site.

Holotype – SWFC 00006804

Basidiomata: Annual, resupinate, adnate, without odour or taste when fresh, becoming fragile to slightly rigid upon drying, up to 12 cm long, 3 cm wide, 1.5 mm thick. Hymenial surface odontioid, vinaceous to brownish vinaceous when fresh, becoming pale brown upon drying, aculei conical, 2–4 per mm, up to 1 mm long. Subiculum very thin to lacking, 50–100 μm thick. Margin pale brown, usually determinate and thinning out. Hyphal structure, hyphal system monomitic; generative hyphae bearing clamp connections, colorless, slightly thick-walled, frequently branched, IKI–, CB+; tissues unchanged in KOH. Hymenium: Cystidia numerous, obviously projecting, cylindrical or tubular, colorless, encrusted, 26–37.5×2.5–4.5 µm; basidia clavate, 13.5–20.5×2.5–4.5 µm, four-spored and with a basal clamp connection; basidioles dominant, in shape similar to basidia, but slightly smaller. Basidiospores broadly ellipsoid to subglobose, colorless, thin-walled, IKI–, CB–, with a distinct apiculus, some bearing a guttule, (3.3–)3.5–4.5(–4.8)×(2.7–)3–3.6(–3.9) µm, L=4.04 µm, W=3.26 µm, Q=1.23–1.25 (n=90/3).

Material examined – CHINA, Yunnan Province, Chuxiong, Zixishan National Forestry Park, on angiosperm trunk, 30 June 2018, C.L. Zhao, CL Zhao 6804 (SWFC 00006804, holotype); Puer, Jingdong County, Huilianghe Village, on fallen branch of angiosperm, 5 January 2019, C.L. Zhao, CL Zhao 9570 (SWFC 00009570, paratype); Yuxi, Xinping County, Mopanshan National Forestry Prk, on angiosperm trunk, 18 January 2018, C.L. Zhao, CL Zhao 6397 (SWFC 00006397, paratype).

GenBank numbers – ITS = MW020702, MW020701, MW020700.

Notes – Phylogenetically, Hyphodontia yunnanensis is sister to H. mollis Sheng H. Wu with 97% MLBS, 100% MPBS, 1.00 BYPP support (Fig. 3). However, H. mollis differs from H. yunnanensis (Figs. 1 and 2) in having the ochraceous, distinctly hydnoid hymenophore with a pink tint and larger basidiospores (4–5.5×3–4 μm, Wu 1990). In addition, the two species share less than 96% in common based on the ITS.

Figure 1 – Hyphodontia yunnanensis (CL Zhao 6804, holotype). a, b Basidiomata. Scale bars: a=2 cm, b=3 mm

Figure 2 – Hyphodontia yunnanensis (drawn from the holotype), microscopic structures. a Basidiospores. b Basidia and basidioles. c Cystidia. d A section of aculei trama. Scale bars: a–d=10 µm

Figure 3 – Maximum parsimony strict consensus tree of Hyphodontia yunnanensis and related species in Hyphodontia based on ITS sequences. The ITS dataset included sequences from 38 fungal specimens representing 24 taxa. Fibrodontia gossypina (GEL 5042) was selected as an outgroup for phylogenetic analyses of ITS phylogenetic trees (Zhao et al. 2014). The PCR procedure and editing the DNA sequences and approaches to phylogenetic analysis from maximum parsimony, maximum Likelihood (ML) and Bayesian inference (BI) followed previous studies (Dai 2012; Zhao and Wu 2017; Cui et al. 2019).The dataset had an aligned length of 755 characters in the dataset, of which 307 characters are constant, 92 are variable and parsimony-uninformative, and 356 are parsimony-informative. Maximum parsimony analysis yielded 1 equally parsimonious tree (TL=1954, CI 0.4417, HI=0.5583, RI=0.6329, RC=0.2795). Best model for ITS estimated and applied in the Bayesian analysis: GTR+I+G, lset nst=6, rates=invgamma; prset statefreqpr=dirichlet (1,1,1,1). Bayesian analysis resulted in the similar topology with an average standard deviation of split frequencies=0.009980 (BI). The ITS region was amplified with primer pairs ITS5 and ITS4 (White et al. 1990). Branches are labeled with maximum likelihood bootstrap values greater than 70% (MLBS), parsimony bootstrap values higher than 50% (MPBS) and Bayesian posterior probabilities greater than 0.95 (BYPP), respectively