Absidia tardiva X. Y. Ji, H. Zhao & X. Y. Liu 2025, sp. nov.
Creators: name: Ji, Xin-Yu
name: Ding, Zi-Ying
name: Nie, Yong
name: Zhao, Heng
name: Wang, Shi
name: Huang, Bo
name: Liu, Xiao-Yong
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Fungi
Zygomycota
Mucoromycetes
Mucorales
Cunninghamellaceae
Absidia
Absidia tardiva

description: Absidia tardiva X. Y. Ji, H. Zhao & X. Y. Liu sp. nov.
Fig. 5
Type.
China, Yunnan Province, Yuxi County, Jinshan National Forest (23°38'15"N, 101°16'30"E, 2397.53 m), from soil, 14 May 2024, X. Y. Ji and X. Y. Liu, holotype HMAS 353358, ex-holotype living culture CGMCC 3.28537 (= XG 08757-4).
Etymology.
The epithet tardiva (Lat.) refers to this species growing more slowly than other strains.
Description.
Colonies on PDA at 26 ° C for 4 days, reaching 41 mm in diameter, slow-growing with a rate of 10.25 mm / d; it begins white and gradually turns pale yellow to grayish-brown, irregular at reverse. Hyphae branched, hyaline at first, brownish when mature, 2.6–10.7 µm (x – = 5.6 µm, n = 20) in diameter, sometimes swollen. Stolons hyaline to brownish, smooth, branched, 3.7–8.4 µm (x – = 5.7 µm, n = 15) in diameter. Rhizoids not observed. Sporangiophores erect or slightly bent, single or 2–4 in whorls, unbranched or simply branched, monopodial or sympodial, with a septum 10.6–23.1 µm (x – = 13.8 µm, n = 15) below apophyses, 7.9–141.9 × 1.9–7.4 µm (x – = 70.7 × 4.2 µm, n = 15), sometimes with a swelling beneath sporangia. Sporangia subspherical to spherical, smooth, multi-spored, 12.9–48.3 × 9.3–34 µm (x – = 30.3 × 22.2 µm, n = 15), deliquescent-walled. Apophyses distinct, subhyaline, small, slightly pigmented, 3.2–10.4 µm (x – = 5.2 µm, n = 15) high, 2.9–7.2 µm (x – = 4.4 µm, n = 15) wide at the base, and 8.0–20.5 µm (x – = 13.2 µm, n = 15) wide at the top. Collars absent. Columellae hemispherical, subhyaline to hyaline, smooth, 2.9–13.8 × 4.9–16.3 µm (x – = 8.7 × 9.8 µm, n = 15). Projections present, shaped like a grain of rice. Sporangiospores variously shaped, mostly ovoid; a few are cylindrical or subglobose, smooth, hyaline, 3.4–4.6 × 2.1–2.8 µm (x – = 3.9 × 2.3 µm, n = 20). Chlamydospores absent. Zygospores not observed.
Maximum growth temperature.
27 ° C.
Additional specimen examined.
China • Yunnan Province, Yuxi County, from soil (23°38'15"N, 101°16'30"E, 2397.53 m), 14 May 2024, X. - Y. Ji and X. - Y. Liu, living culture XG 08757-6.
Notes.
Phylogenetic analysis of five genes showed that A. tardiva was closely related to A. psychrophilia (Zhao et al. 2022 b). Morphologically, the sporangia shape of A. psychrophilia was pyriform, while the sporangia of A. tardiva were hemispherical to spherical in shape. And the distance between the septum and apophysis was shorter in A. psychrophilia than in A. tardiva (10–17 µm vs. 10.6–23.1 µm). The columellae of A. psychrophilia were larger than those of A. tardiva (6.5–30 μm in diameter vs. 2.9–13.8 × 4.9–16.3 μm). The overall size of spores in A. psychrophilia was slightly larger than that in A. tardiva (long: 3.8–5 × 2.2–3.5 µm vs. wide: 3.4–4.6 × 2.1–2.8 µm); the shape of sporangiospores in A. psychrophilia was cylindrical, whereas the shape of spores in A. tardiva was oval.
description: Published as part of Ji, Xin-Yu, Ding, Zi-Ying, Nie, Yong, Zhao, Heng, Wang, Shi, Huang, Bo & Liu, Xiao-Yong, 2025, Unveiling species diversity within early-diverging fungi from China V: Five new species of Absidia (Cunninghamellaceae, Mucoromycota), pp. 267-288 in MycoKeys 117 on pages 267-288, DOI: 10.3897/mycokeys.117.149185