Absidia hainanensis X. Y. Ji, H. Zhao & X. Y. Liu, 2025

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), MycoKeys 117, pp. 267-288 : 267-288

Absidia hainanensis X. Y. Ji, H. Zhao & X. Y. Liu sp. nov.

Fig. 3

Type.

China • Hainan Province, Danzhou City, Tropical Botanical Garden (19°30'42"N, 109°30'3"E, 168.7 m), from soil, 26 Jun. 2024, X. Y. Ji and X. Y. Liu, holotype HMAS 353362 , ex-holotype living culture CGMCC 3.28535 (= XG 06908-1 ) .

Etymology.

The hainanensis (Lat.) refers to Hainan Province of China, where the type was collected.

Description.

Colonies on PDA at 26 ° C for 5 days, reaching 75 mm in diameter, fast growing with a rate of 15 mm / d, at first white, becoming grayish-brown when old. Hyphae hyaline at first, becoming light brown when mature, 2.5–10.2 µm (x – = 5.2 µm, n = 20) in diameter. Rhizoids root-like, simply branched. Stolons hyaline, smooth, branched, 2.9–10.1 µm (x – = 6.1 µm, n = 15) in diameter. Sporangiophores erect or slightly bent, mostly unbranched or simply branched, smooth, monopodial or sympodial, single or 2–4 in whorls, 18.8–159.2 × 1.9–3.7 µm (x – = 75.4 × 2.8 µm, n = 15). Sporangia spherical to subspherical, smooth, hyaline, deliquescent-walled, 15.1–35.2 × 14.3–29.4 µm (x – = 24.2 × 22.1 µm, n = 15), and with a septum 11.5–24.2 µm (x – = 17.0 µm, n = 15) below apophyses. Apophyses obvious, funnel-shaped, 3.3–5.1 µm (x – = 4.6 µm, n = 15) high, 2.5–8.5 µm (x – = 4.3 µm, n = 15) wide at the base, and 7.5–17.4 µm (x – = 11.0 µm, n = 15) wide at the top, light brown, hyaline. Collars present. Columellae mostly oval, 3.9–13.9 × 8.6–19.5 µm (x – = 6.3 × 10.7 µm, n = 15). Projections absent or present, hyaline, single. Sporangiospores ovoid to cylindrical, smooth, hyaline, 3.1–3.7 × 1.9–2.5 µm (x – = 3.6 × 2.2 µm, n = 20). Chlamydospores absent. Zygospores not found.

Maximum growth temperature.

34 ° C.

Additional specimen examined.

China • Hainan Province, Danzhou City (19°30'42"N, 109°30'3"E, 168.7 m), from soil, 26 June 2024, X. Y. Ji and X. Y. Liu, living culture XG 06908-4 .

Notes.

In the molecular phylogeny, A. hainanensis was closely related to A. oblongispora ( Zong et al. 2021) . Morphologically, the sporangiophores of A. hainanensis were at most four in whorls, while those of A. oblongispora were at most five in whorls. Additionally, the maximum length of the sporangiophores in A. oblongispora was significantly greater than that in A. hainanensis (300 µm vs. 159.2 µm). The sporangiospore size was smaller in A. hainanensis (3.1–3.7 × 1.9–2.5 μm vs. 3.5–4.5 × 2.5–8.5 μm). The A. hainanensis has wider columellae (8.6–19.5 µm vs. 8.5–16.5 µm). Physiologically, the maximum growth temperature of A. hainanensis was higher (34 ° C vs. 32 ° C).

Figures

Figure 3. Absidia hainanensis ex-holotype CGMCC 3.28535 a, b colonies on PDA (a obverse b reverse) c, d sporangia e – g columellae h rhizoids i sporangiospores; Scale bars: 10 µm (c – i).