Odentinium cremeum Y. L. Deng & C. L. Zhao, 2025

Deng, Yinglian, Chen, Meng, Wang, Kaisheng, Liu, Wanting, Chen, Daxiang, Yang, Shunqiang, Li, Wenli, Zhou, Hongmin & Zhao, Changlin, 2025, Morphological and phylogenetic analyses reveal one new genus and six new species in Irpicaceae and Steccherinaceae (Polyporales, Basidiomycota) from the Yunnan – Guizhou Plateau, Asia, IMA Fungus 16, pp. e 172367-e 172367 : e172367-

Odentinium cremeum Y. L. Deng & C. L. Zhao sp. nov.

Figs 7 , 8

Diagnosis.

Odentinium cremeum differs from other species by its cream to slightly buff hymenophore, clamed generative hyphae, and ellipsoid basidiospores (3.5–4.5 × 3–3.5 µm).

Etymology.

Cremeum (Lat.): referring to the species having cream-colored hymenial surface.

Type.

CHINA • Yunnan Province, Zhaotong, Qiaojia County, Yaoshan Town, Yaoshan National Nature Reserve , GPS coordinates: 27°08'N, 103°09'E, altitude 2220 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 22 August 2020, CLZhao 20573 ( SWFC) .

Description.

Basidiomata annual, resupinate, leathery, up to 6.5 cm long, 3 cm wide, and 200 µm thick. Hymenial surface odontioid, aculei 3–4 per mm, the length of aculei up to 0.1 mm, slightly cream when fresh, turning to cream upon drying. Sterile margin white to slightly cream, thin, up to 1 mm. Hyphal system monomitic; generative hyphae with clamp connections, colorless, thin-walled, and strongly encrusted with crystals, moderately branched, interwoven, 1.5–4 µm in diameter, IKI –, CB –; tissues unchanged in KOH. Cystidia numerous, thick-walled, cylindrical, strongly encrusted entirely, 84–188 × 7–13 µm, cystidioles absent. Basidia clavate, with 4 sterigmata and a basal clamp connection, 12–21 × 5–6 µm, smooth, thin-walled, basidioles dominant, in shape similar to basidia, but slightly smaller. Basidiospores ellipsoid, colorless, thin-walled, smooth, with one oil drop, IKI –, CB –, 3.5–4.5 × 3–3.5 µm, L = 4.1 µm, W = 3.16 µm, Q = 1.29–1.33 (n = 150 / 5).

Additional specimens examined ( Paratypes).

CHINA • Yunnan Province, Qujing, Qilin District, Cuishan Forest Park , 25°32'38.645"N, 103°41'28.860"E,, altitude 2245 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 5 November 2022, CLZhao 26660 ( SWFC) , Zhaotong, Wumeng Mountain National Nature Reserve , 27°19'24.215"N, 103°43'1.178"E, altitude 2200 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 26 August 2023, CLZhao 31635 ( SWFC) , 29 August 2023, CLZhao 32563 ( SWFC) , Zhaotong, Qiaojia County, Yaoshan Town, Yaoshan National Nature Reserve , GPS coordinates: 27°08'N, 103°09'E, altitude 2220 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 22 August 2020, CLZhao 20648 ( SWFC) .

Notes.

The phylogenetic analysis (Fig. 3 ) showed that Odentinium cremeum was sister to O. aurantium . However, morphologically, O. aurantium can be distinguished by a cream to pale yellow odontioid hymenial surface, aculei 4–6 per mm, narrower clavate basidia (11–23 × 4–4.5 µm vs. 12–21 × 5–6 µm), and globose basidiospores.

Figures

Figure 3. Maximum parsimony strict consensus tree illustrating the phylogeny of Efibula and related species based on ITS + nLSU sequences. Branches are labeled with maximum likelihood bootstrap values higher than 70 % and Bayesian posterior probabilities higher than 0.95, respectively. The new species are shown in bold.

Figure 7. Odentinium cremeum (holotype, CLZhao 20573). a basidiomata. b macroscopic characteristics of hymenophore. Scale bars: 1 cm (a); 1 mm (b).

Figure 8. Microscopic structures of Odentinium cremeum (holotype, CLZhao 20573). a basidiospores. b basidia and basidioles. c cystidia. d a section of the hymenium. Scale bars: 5 µm (a); 10 µm (b – d).