Gymnoascus flavus
Gymnoascus flavus Z.F. Zhang & L. Cai, sp. nov.
Index Fungorum number: 556397, Facesofungi number: FoF 08430; Fig. X
Etymology: Referring to the color of its conidia, yellow.
Holotype: HMAS 248010.
Hyphae pale yellow to yellow, septate, branched, smooth or slightly rough, 1.5–5.0 µm diam.; racquet hyphae present, ‘racquet’ up to 11.0 μm wide. Asexual morph Fertile mycelia usually gathered into special, superfcial yellow structure, where conidia borne mostly. Conidia mostly terminal or lateral, occasionally intercalary, sessile or borne on short protrusions or side branches, unicellular, pyriform, ellipsoidal or globose, smooth, thick-walled, hyaline initially, then becoming yellow, 4.5–7.0 × 4–6 µm (x̄ ± SD = 6.0 ± 0.62 × 5.1 ± 0.64 µm, n = 60), with truncated base. Sexual morph not observed. Culture characteristics—Colonies on PDA attaining 26–34 mm diam. after 3 weeks, coriarious, plicated in center, margin entire, beige (1A2) to salmon (6A3), aerial mycelia sparse. Reverse beige (1A2) to orange (6A3).
Colonies on OA not growing. Colonies on SNA attaining 24–27 mm diam. after 10 days, powdery, margin rhizoids, white initially, becoming light yellow (2A3-2A5) when sporulation, aerial mycelia sparse. Reverse white to pale yellow (2A3). Sporulation within 2 weeks on SNA.
Material examined: CHINA, Sichuan, Xingwen, Feng Cave, N 28.186°, E 105.148°, on soil, May 2016, Z.F. Zhang, HMAS 248010 (holotype designated here), ex-type living culture CGMCC3.19574 = LC12500; Sichuan, Xingwen, Tianliang Cave, N 28.19°, E 105.139°, on soil, May 2016, Z.F. Zhang, LC12511.
Notes: Phylogenetically, Gymnoascus flavus forms a distinct clade sister to G. exasperates Z.F. Zhang, F. Liu & L. Cai, G. reessii and G. uncinatus Eidam based on ITS and LSU sequences . However, dissimilar to G. reessii and G. uncinatus, the sexual morph of G. favus was not observed despite repeated attempts using OA, PDA and SNA media, as well as horse hair and chicken feather as inducers (Orr and Kuehn 1972). Conidia of Gymnoascus flavus are mostly terminal or lateral, as compared to the abundant intercalary conidia of G. exasperates.
Fig. X Gymnoascus flavus (from ex-holotype CGMCC3.19574). a, b Upper and reverse views of cultures on PDA and SNA 4 weeks after inoculation; c fertile mycelia on SNA; d, e terminal and lateral conidia; f conidia. Scale bars: d–f 10 μm
Retrieved from:
Zhang ZF, Zhou SY, Eurwilaichitr L, Ingsriswang S et al. 2021 – Culturable mycobiota from Karst caves in China II, with descriptions of 33 new species. Fungal Diversity 106(1), 29-136. https://doi.org/10.1007/s13225-020-00453-7
References
Orr GF, Kuehn HH 1972 – Notes on Gymnoascaceae. II. Some Gymnoascaceae and keratinophilic fungi from Utah. Mycologia 64,55–72
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