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

Fig. 4

Etymology.

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

Holotype.

MFLU 25-0076 .

Description.

Saprobic on the decaying branch of Mimusops elengi . Sexual morph: Ascomata 286–370 μm high, 364–455 µm wide, (xˉ = 321 × 397 µm, n = 5), immersed, visible as black spots with tiny pores, staining the host surface pale reddish brown around the ostioles, solitary, scattered to aggregated, globose to sub-globose. Ostiole central, prominent, 150–166 μm high, 82–84 µm wide (xˉ = 154 × 82 µm, n = 5). Peridium 12–25 µm (xˉ = 20 µm, n = 5), two-layered; outer layer thick, dense, reddish-brown cells of textura angularis, inner layer thin, cells hyaline, of textura angularis. Paraphyses 3–6 µm wide (xˉ = 4.2 µm, n = 5), hyaline, septate, longer than asci and embedded in a gelatinous matrix. Asci 126–164 × 8–13 µm (xˉ = 145.7 × 10. 2 µm, n = 20), 8 - spored, unitunicate, cylindrical, with short pedicel, apically rounded, with a J +, discoid, apical ring. Ascospores 18–22 × 5–7 µm (xˉ = 20 × 6 µm, n = 20), uniseriate, cylindrical to oblong, hyaline when immature, turning subhyaline to brown at maturity, 1 - septate, slightly constricted at the septum, guttulate, smooth-walled, lacking a sheath in Indian ink. Asexual morph: Not observed.

Material examined.

Thailand • Chiang Rai Province, Mae Fah Luang University ( 20°02′42″N, 99°53′41″E), on the dead, decaying twigs of Mimusops elengi ( Sapotaceae ), 2 October 2023, ZL Tun P 3 ( holotype MFLU 25-0076 ) .

Additional specimens examined.

Thailand • Chiang Rai Province, Mae Fah Luang University ( 20°02′42″N, 99°53′41″E), on the dead decaying branch of Mimusops elengi ( Sapotaceae ), 2 October 2023, ZL Tun P 3 A ( MFLU 25-0159 ) .

Notes.

Amphisphaeria mimusopis is sister to A. flava ( MFLU 18-0102 ) with 100 % ML and 1.00 PP bootstrap support (Fig. 1 ). The interspecies genetic distances between A. mimusopis ( MFLU 25-0076 ) and A. flava ( MFLU 18-0102 ) showed the following base pair differences (without gaps): 1.4 % across LSU (13 / 892 bp) and 6.7 % across ITS (37 / 530 bp). Amphisphaeria mimusopis can be distinguished from A. flava by having larger ascospores (18–22 × 5–7 µm vs 13–16 × 5–7 μm) ( Samarakoon et al. 2019). Amphisphaeria mimusopis has narrower paraphyses (3–6 µm) than A. flava (7–16.3 µm) ( Samarakoon et al. 2019). The ascomata of A. mimusopis produce a pale reddish-brown pigment surrounding the ostioles, whereas A. flava results in a pale-yellow pigmentation on the surface ( Samarakoon et al. 2019). Based on morphological and phylogenetic evidence, as well as the recommendations for species delineation by Chethana et al. (2021), we establish Amphisphaeria mimusopis 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 4. Amphisphaeria mimusopis (MFLU 25-0076, holotype). A. Decaying dead branch; B. Appearance of ascomata on host (arrows indicate the ostiolar openings); C, D. Vertical section through an ascoma; E. Vertical section of ascomatal wall; F. Paraphyses; G. J + Apical ring; H, I. Asci; J – O. Ascospores. Scale bars: 500 μm (C); 200 μm (D); 10 μm (E); 5 μm (F, G); 50 μm (H, I); 20 μm (J – O).