Amphisphaeria schimae Z. L. Tun & K. D. Hyde, 2025

Tun, Zaw Lin, Bundhun, Digvijayini, Bhunjun, Chitrabhanu S., Maharachchikumbura, Sajeewa S. N., Thiyagaraja, Vinodhini, Al-Otibi, Fatimah & Hyde, Kevin D., 2025, The addition of six novel species and a new record of Amphisphaeria from northern Thailand, MycoKeys 125, pp. 1-31 : 1-31

Amphisphaeria schimae Z. L. Tun & K. D. Hyde sp. nov.

Fig. 8

Etymology.

The epithet refers to the host genus, Schima , from which the fungus was isolated.

Holotype.

MFLU 25-0070 .

Description.

Saprobic on decaying twigs of Schima wallichii . Sexual morph: Ascomata 480–620 μm high × 520–683 µm wide, (xˉ = 531 × 583 µm, n = 5), immersed with ostiole breaking through host surface, visible as black spot, solitary to aggregated, scattered, globose to subglobose, brown, ostiolate. Ostiole central, comprising a short papilla, with an ostiolar canal. Peridium 13–16 µm wide (xˉ = 14.2 µm, n = 5), two-layered; outer layer thick, dense, reddish-brown cells of textura angularis, inner layer thin, hyaline cells of textura angularis. Paraphyses 3–5 µm wide, hyaline, filiform, septate, embedded in a gelatinous matrix. Asci 196–275 × 21–30 µm (xˉ = 236.2 × 22.9 µm, n = 20), 8 - spored, unitunicate, cylindrical, with short pedicel, apically rounded, with J-, apical ring. Ascospores 36.9–40 × 13.5–15 µm (xˉ = 38.6 × 14 µm, n = 20), uniseriate, broadly fusiform, hyaline, turning olivaceous brown to brown at maturity, one median and constricted euseptum, with two distosepta, guttulate (especially at immaturity), broad to conically rounded at both ends, smooth, surrounded by a thick mucilaginous sheath. Asexual morph: Not observed.

Culture characteristics.

Colonies on MEA slow-growing, reaching 3 cm in diam. after 15 days at 27 ° C, from above white to pale yellow radiating outwards, dense, circular, irregular, flattened with smooth surface, with lobate margin; reverse yellow brown in the middle, white at the margin.

Materials examined.

Thailand • Chiang Mai Province, in forests around the Mushroom Research Center ( 19°07.200'N, 98°44.044'E), on fallen dead twigs of Schima wallichii ( Theaceae ), 14 November 2022, Zaw Lin Tun C 1 ( holotype MFLU 25-0070 ), ex-type culture MFLUCC 25-0196 .

Additional specimens examined.

Thailand • Chiang Mai Province, in forests around the Mushroom Research Center ( 19°07.200'N, 98°44.044'E), on fallen dead twigs of Schima wallichii ( Theaceae ), 14 November 2022, Zaw Lin Tun C 2 ( MFLU 25-0071 ) .

Notes.

Based on our phylogenetic analyses, Amphisphaeria schimae ( MFLU 25-0071 , MFLUCC 25-0196 ) is sister to A. ailaoshanensis ( KUNCC 23-15520 , KUNCC 23-15521 ) (Fig. 1 ). However, A. schimae can be distinguished from A. ailaoshanensis by having larger ascomata (480–620 μm high × 520–683 μm vs. 100–140 μm high × 250–350 μm), asci (196–275 × 21–30 μm vs. 70–100 × 7–10 μm), and ascospores (36.9–40 × 13.5–15 μm vs. 14–20 × 5–8 μm) ( Dissanayake et al. 2024). Additionally, the ascospores of A. schimae are broadly fusiform, hyaline, turning olivaceous brown to brown at maturity, with one median, conspicuously constricted euseptum, and surrounded by a thick mucilaginous sheath, whereas those of A. ailaoshanensis are fusiform, hyaline, guttulate, turning brown, 1–3 - septate, and lack a mucilaginous sheath ( Dissanayake et al. 2024). When comparing base pair differences (excluding gaps) between A. schimae ( MFLUCC 25-0196 ) and A. ailaoshanensis ( KUNCC 23-15520 , KUNCC 23-15521 ), there is a 4.9 % divergence in the LSU region (34 / 690 bp) and 8.2 % divergence in the ITS region (43 / 525 bp). Based on the distinct morphological and phylogenetic evidence, along with the species delineation guidelines proposed by Chethana et al. (2021), we describe A. schimae as a new species.

Figures

Figure 1. Phylogram generated from ML analysis based on combined LSU, ITS sequence data. Bootstrap support values for ML ≥ 75 % and PP ≥ 0.90 are indicated near the corresponding nodes. The tree is rooted with Beltrania rhombica (CBS 123.58), Beltraniella endiandrae (CBS: 137976), and Beltraniopsis longiconidiophora (MFLUCC 17-2139). Type and reference strains are in bold, while the novel strains are in bold red.

Figure 8. Amphisphaeria schimae (MFLU 25-0070, holotype). A. Host; B. Close-up of ascoma on host (Arrow indicates ascoma visible as a black spot, with ostiole breaking through the host); C. Vertical section of an ascoma; D. Ostiole; E. Vertical section of peridium; F. Paraphyses; G – I. Asci (I in Melzer’s reagent); J – N. Ascospores with sheaths; O. Germinated ascospore; P. Upper view of culture; Q. Reverse view of culture. Scale bars: 100 μm (C); 20 μm (D); 10 μm (E, F); 50 μm (G – I); 20 μm (J – O).