Pseudorhypophila formosana K. W. Cheng & H. A. Ariyaw., 2025

Cheng, Kai-Wen, Yang, Jiue-in, Srimongkol, Piroonporn, Stadler, Marc, Karnchanatat, Aphichart & Ariyawansa, Hiran A., 2025, Fungal frontiers in toxic terrain: Revealing culturable fungal communities in Serpentine paddy fields of Taiwan, IMA Fungus 16, pp. e 155308-e 155308 : e155308-

Pseudorhypophila formosana K. W. Cheng & H. A. Ariyaw. sp. nov.

Fig. 34

Typification.

TAIWAN • Guanshan Township , Taitung County, 23°02'14.8"N, 121°11'22.6"E, serpentine soil in rice field, 3 rd November 2022, K. W. Cheng, holotype, NTUPPMH 22-226 (Permanently preserved in a metabolically inactive state), ex-holotype NTUPPMCC 22-297 , ex-isotype NTUPPMCC 22-295 , 296, 298 to 300 .

Etymology.

Named after Formosa, the former name of Taiwan, where the type specimen was collected.

Description.

Sexual morph Ascomata 342–504 µm diam, non-ostiolate, globose, dirty gray when immature, black when mature, submerged in PDA. Peridium multi-layered, brown, translucent, membranous, angular cells. Asci clavate to cylindrical, hyaline when immature, eight-spored, 74–111 µm × 14–21 µm (x ̄ = 90.9 × 17.8 µm, L / W ratio = 5.13, n = 20). Ascospores two-celled; upper cell ellipsoidal to slightly fusiform, smooth, brown, multiple guttules, subapical germ pore, 18.3–24.6 µm × 8.8–12.5 µm (x ̄ = 21.3 × 11.0 µm, L / W ratio = 1.95, n = 50), lower cell cylindrical with slightly tapering or rounded end, hyaline to pale brown, thin-walled, 4.0–8.0 µm × 3.1–5.8 µm (x ̄ = 5.8 × 4.3 µm, L / W ratio = 1.36, n = 50). Asexual morph undetermined.

Culture characteristics.

Colony exhibit rapid growth, reaching 80 mm diam with flat, sparse aerial mycelium, white, surface and margins slight smooth. The reverse exhibited blackish-gray center, with a gradient radiating outward into lighter gray tones.

Notes.

In the present study, six Pseudorhypophila strains ( NTUPPMCC 22-295 to 300) formed a distinct clade with a strong statistical support (100 % / 1.00), clearly separating from known Pseudorhypophila species in the multi-locus phylogenetic analysis (Fig. 35 ). Furthermore, the ex-type strain of Pseudorhypophila formosana ( NTUPPMCC 22-297 ) exhibits significant genetic divergence from its closest relatives, the ex-type strains of P. mangenotii ( CBS 419.67 ) and P. poae ( CMML 20-36 ), with 94.0 % (936 / 996 bp) and 94.2 % (938 / 996 bp) identity, respectively, in the rpb 2 gene. In line with earlier research on P. marina and P. pilifera , our isolate produces ascomata lacking ostioles and bearing 2 - celled ascospores, a distinctive trait of the Pseudorhypophila ( Harms et al. 2021) . However, P. formosana NTUPPMCC 22-297 is distinguished by its lower cell lengths, which are noticeably smaller than those of the type species, P. marina CBS 698.96 (4–8 µm × 3–6 µm versus 6–13 µm × 3–5 µm) (Fig. 34 ; Guarro et al. 1997). Moreover, P. poae has been recorded only in its asexual morph, which was not observed in our strains ( NTUPPMCC 22-295 to 300). Notably, the other representative strain of P. marina ( Zopfiella marina CBS 155.77 ) was previously reported from Taiwan. However, it also differs from P. formosana NTUPPMCC 22-297 in morphology, phylogeny and habitat (marine mud versus terrestrial serpentine soil) ( Overy et al. 2014; Harms et al. 2021).

Figures

Figure 34. Morphology of Pseudorhypophila formosana NTUPPMCC 22-297. A, B 14 - days-old colony on PDA; C Ascomata; D Immature ascomata; E Squashed ascomata; F, G Immature ascus; H, I Ascus; J Ascospores; K, L Ascospores (red arrows: subapical germ pores). Scale bars: 0.5 mm (C); 100 µm (E); 20 µm (D, F – I); 10 µm (J); 5 µm (K – L).

Figure 35. Maximum likelihood (ML) phylogenetic tree based on a concatenated dataset of ITS, LSU, and rpb 2. In total, 23 strains representing 16 taxa were included in the concatenated dataset, with 2444 characters (ITS 569 bp, LSU 869 bp, and rpb 2 1006 bp) including alignment gaps. The tree was rooted with Corylomyces selenosporus CBS 113930. MLB ≥ 70 % and BPPs ≥ 0.95 were shown at each node; values lower than these thresholds are indicated by a hyphen (–). The scale bar indicates the number of estimated substitutions per site. The strains introduced in this study are in red and novel species are in bold. The ex-type strains are marked with T.