Gongronella reniformis Yi Xin Wang, H. Zhao & X. Y. Liu 2024, sp. nov.

Gongronella reniformis Yi Xin Wang, H. Zhao & X. Y. Liu sp. nov. Fig. 8 Etymology. The epithet “ reniformis “ (Latin) refers to the reniform sporangiospores. Type. China • Hainan Province, Changjiang Li Autonomous County, Qicha Town (19.11750 ° N, 109.15000 ° E), from soil sample, 11 April 2023, Yi-Xin Wang (holotype HMAS 352727, ex-holotype strain CGMCC 3.27030). Description. Colonies on PDA in darkness at 25 ° C growing slowly, reaching 39.4–41.8 mm in diameter in seven days, white, regular at edge and cottony in the centre, on reverse milky white. Rhizoids hyaline, branched, irregular, sometimes with giant cells in the terminal. Stolons absent. Sporangiophores on aerial mycelia, erect or slightly curved, unbranched or slightly branched (1–3 times), 3.4–157.9 × 0.8–3.4 μm, hyaline, smooth, mostly aseptate, partially no more than two-septate. Sterile (aborted) sporangia predominantly on the top of short lateral branches of sporangiophores, gourd-shaped, 15.0–19.9 × 3.1–10.9 μm. Fertile sporangia hyaline or light yellow, spherical, 7.9–26.0 μm in diameter, smooth and deliquescent-walled, leaving a collar after releasing sporangiospores. Columellae mostly elliptic, 1.7–4.6 × 1.4–5.2 μm, sometimes sub-hemispherical, 1.4–2.6 × 3.3–4.9 μm, hyaline, smooth. Collars distinct, 2.1–4.3 μm. Apophyses hyaline, smooth, variously shaped, pear-shaped, 3.3–8.5 × 3.0–7.3 μm, ellipsoidal, 4.6–10.1 × 2.9–7.8 μm. Sporangiospores not uniform, hyaline, smooth, mostly reniform, 2.8–3.5 × 1.8–2.3 μm, occasionally ovoid, 3.1–3.4 × 1.7–2.0 μm. Chlamydospores, mostly ellipsoidal, 7.3–12.5 × 6.1–11.2 μm, sometimes irregular. Giant cells intercalary, globose, 3.5–10.0 μm in diameter. Zygospores not found. Additional specimen examined. China • Hainan Province, Changjiang Li Autonomous County, Qicha Town (19.11750 ° N, 109.15000 ° E), from soil sample, 11 April 2023, Yi-Xin Wang (living culture SAUCC 4142-5). GenBank accession numbers. CGMCC 3.27030 (ITS, PP 195851; LSU, PP 195952; TEF, PP 850095; ACT, PP 933943; RPB 1, PP 84875), SAUCC 4142-5 (ITS, PP 195852; LSU, PP 195953; TEF, PP 850096; ACT, PP 933944; RPB 1, PP 842876). Notes. Based on phylogenetic analyses of ITS + LSU + TEF + ACT + RPB 1 sequences, the two isolates of the new species Gongronella reniformis form an independent clade with full support (MLBV = 100, BIPP = 1; Fig. 1), which is close to G. pamphilae and G. brasiliensis with a high support (MLBV = 89, BIPP = 1; Fig. 1). Comparing ITS sequences showed that G. reniformis is relatively closely related to G. pamphilae (44 bp of dissimilarity) and G. brasiliensis (40 bp of dissimilarity). There were no morphological descriptions of G. pamphilae in its protologue, so the morphological comparison was made between G. reniformis and the G. pamphilae strains identified in this study. This new species differs morphologically from G. pamphilae in sporangium, columellae, apophysis, sporangiospore. The sporangium of G. reniformis is smaller than that of G. pamphilae (7.9–26.0 μm vs. 13.8–30.8 μm). G. reniformis and G. pamphilae are different from each other mainly in shape and size of columellae, the former being mostly elliptic, 1.7–4.6 × 1.4–5.2 μm, sometimes sub-hemispherical, 1.4–2.6 × 3.3–4.9 μm and the latter being mostly hemispherical, 1.8–4.7 × 2.0–7.7 μm, sometimes arc-shaped, 0.5–1.6 × 3.3–4.6 μm. The G. reniformis and G. pamphilae are different from each other in dominant shape and size of apophyses, the former being pear-shaped, 3.3–8.5 × 3.0–7.3 μm and ellipsoidal, 4.6–10.1 × 2.9–7.8 μm, the latter being spherical, 5.7–8.1 × 5.6–9.0 μm and ellipsoidal, 4.8–6.9 × 4.8–6.1 μm. The sporangiospores of G. reniformis are smaller than those of G. pamphilae (reniform, 2.8–3.5 × 1.8–2.3 μm vs. 3.0–5.5 × 1.8–3.4 μm, ovoid, 3.1–3.4 × 1.7–2.0 μm vs. 2.5–5.6 × 1.8–3.7 μm). This new species differs morphologically from G. brasiliensis in sporangiophore, columellae and giant cells (Tibpromma et al. 2017). In sporangiophores, the G. renformis differs from the G. brasiliensis in size, 3.4–157.9 × 0.8–3.4 μm vs. 26.5–320.0 × 2.5–5.0 μm. As for columellae, the G. renformis and G. brasiliensis are different in shape. The former mostly elliptic, sometimes sub-hemispherical. The latter globose, subglobose and conical-cylindrical. The G. renformis is evidently smaller than G. brasiliensis in giant cells, 3.5–10.0 μm vs. up to 48 μm. Combining morphological and molecular phylogenetic analyses, we classified the two isolates as a new species G. reniformis.