Absidia crystalloides M. F. Tao, H. Zhao & X. Y. Liu, 2024

Tao, Meng-Fei, Ding, Zi-Ying, Wang, Yi-Xin, Zhang, Zhao-Xue, Zhao, Heng, Meng, Zhe & Liu, Xiao-Yong, 2024, Unveiling species diversity within early-diverging fungi from China II: Three new species of Absidia (Cunninghamellaceae, Mucoromycota) from Hainan Province, MycoKeys 110, pp. 255-272 : 255-272

Absidia crystalloides M. F. Tao, H. Zhao & X. Y. Liu sp. nov.

Fig. 3

Type.

China • Hainan Province, Changjiang County, Bawangling National Forest Park (19.08593 ° N, 109.12275 ° E), from soil, 14 Oct 2023, M. F. Tao and X. Y. Liu, holotype HMAS 352925 , ex-holotype living culture CGMCC 3.27496 , living cultures XG 06948-15 or SAUCC 6948-15 .

Etymology.

The epithet crystalloides (Lat.) refers to the crystal-like projections.

Description.

Mycelia white at first and gradually turning to dark brown, branched, subhyaline to hyaline, aseptate or irregularly septate with age. Rhizoids well-developed, root-like, branched. Stolons hyaline, branched, brownish, smooth, 3.1–7.8 µm in diameter. Sporangiophores growing on stolons, mostly unbranched or simply branched, erect or slightly bent, smooth, single or 2–4 in whorls, 55.8–109.3 µm long, 2.6–4.7 µm wide, with one septum 12.8–24.1 µm below sporangia. Sporangia mainly globose, rarely pyriform, dark brown, smooth, subhyaline, deliquescent-walled, 23.0–28.0 µm long, 23.4–28.0 µm wide. Apophyses distinct, light brown, subhyaline, 3.9–9.4 µm wide at the base and 7.4–17.8 µm wide at the top. Collars clearly present, hyaline. Columellae subglobose to globose, smooth, 9.7–12.6 µm long, 11.7–19.5 µm wide. Projections present or absent, if present, single, crystal-like, 3.1–3.5 µm long, 1.8–2.2 µm wide. Sporangiospores smooth, hyaline, oval or fabiform, exhibiting a slight constriction at the center, 3.1–4.1 µm long, 2.1–2.8 µm wide. Chlamydospores absent. Zygospores not found.

Culture characteristics.

Colonies on PDA at 25 ° C for 7 days, reaching 65 mm in diameter, exhibiting an average growth rate of approximately 8.6–9.3 mm / d, white initially, gradually becoming dark brown when mature, irregularly concentrically zonate with ring, irregularly in reverse.

Maximum growth temperature.

32 ° C.

Additional specimen examined.

China • Hainan Province, Changjiang County, Bawangling National Forest Park (19.08593 ° N, 109.12275 ° E), from soil, 14 Oct 2023, M. F. Tao and X. Y. Liu, living culture XG 06932-1 or SAUCC 693201 , XG 06948-17 or SAUCC 6948-17 .

Notes.

Phylogenetically, A. crystalloides was closely related to A. oblongispora and A. heterospora . Compared with A. oblongispora , the A. crystalloides exhibited a smaller stolon diameter (3.1–7.8 µm vs 4.0–9.5 µm), the septum was positioned at a greater distance from apophyses (12.8–24.1 µm vs 9.5–16.0 µm), while sporangiophores were located at a shorter distance (55.8–109.3 µm vs 33.0–300.0 µm), apophyses had a wider base width (3.9–9.4 µm vs 3.5–7.5 µm). Physiologically, the maximum growth temperature of A. crystalloides was higher (32 ° C vs 31 ° C). In comparison to A. heterospora , the A. crystalloides possessed two forms of sporangiospores and had a smaller columella diameter (11.7–19.5 µm vs 10.5–34 µm) ( Hesseltine and Ellis 1964; Zhao et al. 2023).

Figures

Figure 3. Absidia crystalloides (holotype: HMAS 352925) a obverse and reverse of the culture on PDA b rhizoids c, d columellae e, f sporangia g sporangiospores. Scale bars: 10 μm (b – g).