Peroneutypa hibisci Apurillo, Phukhams., E. B. G. Jones & K. D. Hyde 2025, sp. nov.

Peroneutypa hibisci Apurillo, Phukhams., E. B. G. Jones & K. D. Hyde sp. nov. Fig. 4 Etymology. Based on the host, Hibiscus tiliaceus. Holotype. MFLU 24-0191. Description. Saprobic on decomposing branches of Hibiscus tiliaceus submerged in brackish water. Sexual morph: Stromata 1.0– 1.5 mm (x ̄ = 1.2, n = 5), poorly developed, non-sulcate, solitary to gregarious, immersed to erumpent, dark brown to black. Perithecia 200–300 µm (x ̄ = 238, n = 5) in diameter, immersed to erumpent, globose, brown to black, ostiolate. Peridium 20–45 µm (x ̄ = 32, n = 5) wide, composed of two layers, outer layer dark brown to black comprising of textura angularis cells, inner layer of textura angularis cells, brown to dark-brown. Hamathecium 90–125 µm × 3–4 µm (x ̄ = 104 × 3.4 µm, n = 5) wide, hyaline, aseptate, unbranched. Asci 57–68 µm × 6–8 µm (x ̄ = 59.4 × 7.6 µm, n = 5), 8 - spored, clavate, unitunicate, short stipitate, with inamyloid apical rings. Ascospores 8–12 µm × 3–4 µm (x ̄ = 10.7 × 3.6 µm, n = 45), hyaline, ellipsoid, with constricted median septum when mature, 2–4 guttules. Asexual morph: Undetermined. Known distribution. Thailand. Culture characteristics. Ascospores germinated in MEA within 24 hours, the germ tubes arising from both ends of the ascospore. Colonies on MEA grow up to 10 cm after 7 days of incubation at room temperature, white, filamentous, with aerial mycelium, reverse with gray pigment toward the center. Material examined. Thailand • Prachuap Khiri Khan: Pranburi District, 12°23'8.74"N, 99°56'51.47"E, on decomposing branches of Hibiscus tiliaceus submerged in brackish water. 4 February 2023, Carlo Chris S. Apurillo, P 20201 (MFLU 24-0191, holotype), ex-type living culture, MFLUCC 24-0514. GenBank Numbers. ITS: PP 989294, tub 2 = PP 993003. Notes. Peroneutypa hibisci formed a lineage with Peroneutypa mangrovei, the latter showing a longer branch length than Peroneutypa hibisci. Although this clade has low support, this was consistently observed in ML, MP and BI trees. Comparison of base pair differences between these two closely related species revealed a difference of 23 out of 459 bases (5.0 %) in ITS and 7 out of 349 bases (2.0 %) in tub 2 sequences. Morphologically, they differ significantly: P. hibisci has larger, ellipsoid, guttulate ascospores (8–12 × 3–4 µm), while P. mangrovei has smaller, cylindrical to clavate ascospores (3–5 × 1–1.5 µm) without guttules. The asci of P. hibisci (57–68 × 6–8 µm) are also much larger than those of P. mangrovei (14–20 × 3–4 µm) (Phookamsak et al. 2019). Compared to another related species, P. polysporae, P. hibisci differs by producing median-septate, ellipsoid ascospores, whereas P. polysporae has smaller, unicellular, allantoid spores. Additionally, P. polysporae has larger asci (110–155 × 5–7.5 µm) than P. hibisci (Dayarathne et al. 2020). Morphological and sequence data support the introduction of Peroneutypa hibisci as a novel species based on the guidelines of Jeewon and Hyde (2016) and Maharachchikumbura et al. (2021).