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

Fig. 5

Etymology.

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

Holotype.

MFLU 25-0075.

Description.

Saprobic on decaying twigs of Paraserianthes lophantha. Sexual morph: Ascomata 430–520 µm wide, 290–400 µm high (xˉ = 497 × 355 µm, n = 5), immersed, solitary or grouped, scattered, globose to subglobose, dark brown to black, ostiolate. Ostiole central, comprising a short papilla, with an ostiolar canal lined with hyaline periphyses. Peridium 16–20 µm (xˉ = 16 µm, n = 5) two-layered; outer layer wide, dark brown, thick-walled cells of textura angularis, inner layer comprising one layer of pale yellow or sub-hyaline to hyaline cells of textura angularis, thin-walled. Paraphyses 3–5 µm wide (xˉ = 4.5 µm, n = 5), hyaline, filiform, septate, guttulate, longer than asci. Asci 85–152 × 7.5–16 µm (xˉ = 125.5 × 10.5 µm, n = 20), 8 - spored, unitunicate, cylindrical, thin-walled, short-pedicellate, apically rounded, with a J +, conspicuous, discoid, apical ring. Ascospores 16–20 × 5–9 µm (xˉ = 19 × 6.9 µm, n = 20), uniseriate, oblong to ellipsoid, hyaline when young, turning yellow brown at maturity, 3 - septate, rounded to obtuse ends, smooth-walled, guttulate, without a sheath. Asexual morph: Not observed.

Material examined.

Thailand • Chiang Mai Province, in the forests around the Mushroom Research Center (19°07.200'N, 98°44.044'E), on fallen decaying twigs of Paraserianthes lophantha (Fabaceae), 14 November 2022, Zaw Lin Tun M 14, (holotype MFLU 25-0075).

Notes.

Amphisphaeria paraserianthis (MFLU 25-0075) formed a distinct lineage that is basal to A. neoaquatica (MFLUCC 14-0045) and A. hongheensis (GMB 1135) (Fig. 1). The interspecies genetic distances between A. paraserianthis and A. neoaquatica (MFLUCC 14-0045) showed the following base pair differences (without gaps): 7 % for LSU (58 / 818 bp) and 5.11 % for ITS (25 / 489 bp). Amphisphaeria paraserianthis and A. hongheensis (GMB 1135) showed the following base pair differences (without gaps): 2.8 % for LSU (26 / 923 bp) and 7.7 % for ITS (35 / 455 bp). The ascomata of A. paraserianthis (430–520 × 290–400 µm) are larger than those of A. neoaquatica (250–320 × 300–330 μm) and smaller than those of A. hongheensis (430–750 × 360–640 μm). The asci of A. paraserianthis (85–152 × 7.5–16 µm) are larger than those of A. neoaquatica (126–138 µm × 8–10 μm), and smaller than A. hongheensis (175-265 × 10–15 µm) (Luo et al. 2019, Liu et al. 2024 a). The ascospores of A. paraserianthis (16–20 × 5–9 µm) are larger than A. neoaquatica (15–17 × 5–7 μm) and smaller than A. hongheensis (20-40 × 5-11 μm) µm (Luo et al. 2019, Liu et al. 2024 a). In addition, A. paraserianthis possesses 3 - septate ascospores while A. neoaquatica and A. hongheensis possess 1 - septate ascospores (Luo et al. 2019, Liu et al. 2024 a). Based on the species delineation suggestions made by Chethana et al. (2021) and the findings from morpho-phylogenetic analyses, we establish A. paraserianthis (MFLU 25-0075) as a new species.