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

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

Fig. 6 View Figure 6

Type.

China • Tibet, Xigaze City, Yadong Country (27°21'53"N, 88°58'26"E, 2827 m), from soil, 1 Oct 2024, X. Y. Ji and X. Y. Liu, holotype HMAS 353361 View Materials , ex-holotype living culture CGMCC 3.28534 View Materials (= XG 00415-1 ) GoogleMaps .

Etymology.

The tibetensis (Lat.) refers to the Tibet Autonomous Region of China, where the type was collected.

Description.

Colonies on PDA at 26 ° C for 5 days, reaching 53 mm in diameter, slow-growing with a rate of 10.6 mm / d, white at first and gradually turning to light brown; the reverse side of the colony resembles a petal-shaped, regularly at reverse. Rhizoids root-like, always branched, with a septum at the top. Hyphae hyaline to slightly gray, 5.0–10.0 µm (x – = 7.1 µm, n = 20) in diameter, sometimes ampulliform-shaped swollen. Stolons hyaline, slightly brownish, branched, smooth, 3.2–11.0 µm (x – = 6.0 µm, n = 15) in diameter. Sporangiophores erect or slightly bent, unbranched or simple branched, smooth, single or 2–5 in whorls, monopodial or sympodial, 14.7–144.0 × 2.5–5.7 µm (x – = 78.2 × 4.0 µm, n = 15), sometimes with a swelling beneath sporangia. Sporangia globose to pyriform, smooth, multi-spored, deliquescent-walled, 11.0–30.2 × 11.1–26.6 µm (x – = 21.5 × 17.1 µm, n = 15), and with a septum 8.4–20.0 µm (x – = 15.6 µm, n = 15) below apophyses. Apophyses obvious, funnel-shaped, gradually widening from the base to the top, 2.5–9.6 µm (x – = 6.7 µm, n = 15) high, 3.2–8.3 µm (x – = 4.2 µm, n = 15) wide at the base, and 7.4–19.0 µm (x – = 11.2 µm, n = 15) wide at the top, hyaline, light brown. Collars absent or present. Columellae conical, nearly globose, occasionally oval, 8.5–19.9 × 10.1–16.5 µm (x – = 11.3 × 11.8 µm, n = 15). Projections present or absent, hyaline when present, needle-pointed. Sporangiospores smooth, hyaline, mostly oval, 2.6–3.9 × 1.6–2.4 µm (x – = 3.6 × 2.1 µm, n = 20). Chlamydospores absent. Zygospores not found.

Maximum growth temperature.

30 ° C.

Additional specimen examined.

China • Tibet, Xigaze City , Yadong County (27°21'53"N, 88°58'26"E, 2827 m), from soil, 1 October 2024, X. Y. Ji and X. Y. Liu, living culture XG 00415-3 GoogleMaps .

Notes.

In the molecular phylogeny, A. tibetensis was closely related to A. sichuanensis ( Zhao et al. 2022 b) . Morphologically, the maximum width of the hyphae in A. yunnanensis was greater than that in A. tibetensis (15.5 µm vs. 10.0 µm). Apophyses had a wider base width and top width in A. tibetensis (3.2–8.3 × 7.4–19.0 μm vs. 3.0–5.0 × 5.5–12.0 μm). The sporangiophore size was smaller in A. tibetensis (2.6–3.9 × 1.6–2.4 μm vs. 3.0–4.5 × 2.0–2.5 μm). The swelling on sporangiophores and hyphae was observed in A. tibetensis . The collars were not observed in A. sichuanensis . Physiologically, the maximum growth temperature of A. tibetensis was higher (30 ° C vs. 28 ° C).