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

Fig. 2

Type.

China • Yunnan Province, Yuxi City, Xinping Yi Dai Autonomous County, Ancient Tea Horse Road (23°57'28"N, 101°30'38"E, 2196.56 m), from soil, 5 Jul. 2024, X. Y. Ji and X. Y. Liu, holotype HMAS 353360 , ex-holotype living culture CGMCC 3.28536 (= XG 08666-10-1 ) .

Etymology.

The collariata (Lat.) refers to its long collars.

Description.

Colonies on PDA at 26 ° C for 5 days, reaching 68 mm in diameter, moderately fast growing with a rate of 13.6 mm / d, higher in the center than at margin, at first white, becoming grayish brown when mature, regular shape at reverse. Hyphae light-colored at first, becoming brown when mature, 4.7–9.4 µm (x – = 6.4 µm, n = 20) wide. Stolons branched, hyaline to light brown, smooth, septate, 5.1–6.3 µm (x – = 5.6 µm, n = 15) in diameter. Rhizoids well developed, root-like, branched. Sporangiophores growing on stolons, erect or slightly bent, mostly unbranched or simply branched, smooth, single or 2–4 in whorls, monopodial or sympodial, 21.7–213.5 × 2.3–5.4 µm (x – = 112.8 × 4.1 µm, n = 15). Sporangia globose to pyriform, smooth, hyaline, deliquescent-walled, 16.2–37.0 × 14.0–31.1 µm (x – = 24.2 × 23.2 µm, n = 15), and with a septum 8.8–17.9 µm (x – = 13.9 µm, n = 15) below apophyses; the septum is not obvious when young. Apophyses distinct, funnel-shaped, 6.0–9.5 µm (x – = 8.5 µm, n = 15) high, 5.1–8.8 µm (x – = 6.2 µm, n = 15) wide at the base, and 8.4–13.9 µm (x – = 10.7 µm, n = 15) wide at the top, darker brown when old. Collars present, obvious. Columellae nearly conical, sometimes subspherical to hemispherical, 8.1–13.8 × 7.7–14.9 µm (x – = 10.6 × 10.9 µm, n = 15). Projections absent or present, hyaline, single. Sporangiospores hyaline, smooth, mostly oval, 2.1–3.8 × 1.8–2.7 µm (x – = 3.1 × 2.3 µm, n = 20). Chlamydospores absent. Zygospores not found.

Maximum growth temperature.

29 ° C.

Additional specimen examined.

China • Yunnan Province, Yuxi City (23°57'28"N, 101°30'38"E, 2196.56 m), from soil, 5 Jul. 2024, X. Y. Ji and X. Y. Liu, living culture XG 08666-10-2 .

Notes.

In the molecular phylogeny, A. collariata was closely related to A. psychrophilia ( Zhao et al. 2022 b) . Morphologically, the width of stolons in A. collariata was smaller than that in A. psychrophilia (5.1–6.3 µm vs. 5.5–11 µm). Furthermore, the A. collariata has smaller sporangiophores (2.1–3.8 × 1.8–2.7 µm vs. 3.8–5 × 2.2–3.5 µm). The length and width of sporangiophore were also smaller in A. collariata than those in A. psychrophilia (21.7–213.5 × 2.3–5.4 µm vs. 193–288 × 4.5–9 µm). And the A. psychrophilia has larger sporangia (20–50 μm vs. 16.2–37.0 × 14.0–31.1 μm). Zygospores were not observed in A. collariata .

Figures

Figure 2. Absidia collariata ex-holotype CGMCC 3.28536 a, b colonies on PDA (a obverse b reverse) c – e sporangia f, g swelling on sporangiophores h – j columellae k rhizoids l sporangiospores. Scale bars: 10 μm (c – l).