Pseudomelanconiella mangrovei Apurillo, Phukhams., E. B. G. Jones & K. D. Hyde 2025, sp. nov.

Pseudomelanconiella mangrovei Apurillo, Phukhams., E. B. G. Jones & K. D. Hyde sp. nov. Fig. 2 Etymology. Based on its mangrove host. Holotype. MFLU 24-0189. Description. Saprobic on decomposing branch of Avicennia marina submerged in brackish water. Sexual morph: Undetermined. Asexual morph: Conidiomata 100–590 µm × 200–815 µm (x ̄ = 386.3 × 566.2 µm, n = 10), globose to subglobose, immersed to erumpent, black, confluent, mostly with a central stromatic column. Peridium light-brown to brown, made of cells of textura angularis. Conidiophores 8–20 × 1–2 µm (x ̄ = 14.6 × 1.8 µm, n = 30), mostly straight, hyaline, septate, smooth unbranched. Conidiogenous cells 2–7 × 1–2 µm (x ̄ = 4.2 × 1.8 µm, n = 30), monophialidic, determinate, discrete, cylindrical to subcylindrical, smooth-walled, hyaline, arising from inner layers of conidioma. Conidia 11–14 × 3–4 µm (x ̄ = 11.4 × 3.3 µm, n = 50), oblong to ellipsoid, hyaline to light-brown, unicellular, aseptate, verrucose, without gelatinous sheath. Known distribution. Thailand. Culture characteristics. Conidia germinate in malt extract agar (MEA) within 24 hours, with germ tubes arising from one end of the conidia. Colonies on MEA grow up to 14 cm after 7 days of incubation at room temperature, circular, mostly flat or effuse with a raised ring near the center, undulate, white, translucent; reverse does not exhibit pigments. Material examined. Thailand • Prachuap Khiri Khan Province, Pranburi District, 12°23'9"N, 99°56'51"E, on decomposing branch of Avicennia marina L. (Acanthaceae) submerged in brackish water, 4 February 2023, Carlo Chris S. Apurillo, P 30201 (MFLU 24-0189, holotype); • ibid., P 30301 (MFLU 24-0190); ex-type living culture MFLUCC 24-0512 = MFLUCC 24-0513. GenBank numbers. MFLU 24-0189 = ITS: PP 989291, LSU: PP 989287, rpb 2: PP 993004, tef 1 - α: PP 993001; MFLU 24-0190 = ITS: PP 989292, LSU: PP 989288, tef 1 - α: PP 993002. Notes. Based on combined analysis of ITS, LSU, rpb 2, and tef 1 - α sequences, Pseudomelanconiella mangrovei formed a distinct clade within Melanconiellaceae, with Septomelanconiella thailandica as the closest taxon. Pseudomelanconiella mangrovei differs from Septomelanconiella thailandica based on the appearance of the conidia. The distinguishing characteristic of S. thailandica is its septate conidia (Phookamsak et al. 2019). In contrast, Pseudomelanconiella mangrovei conidia are aseptate. While the morphology of Pseudomelanconiella mangrovei is similar to Melanconiella species, particularly the appearance of conidiomata, conidiogenous cells and the shape of the conidia, its phylogenetic position is distinct from other Melanconiella species (Voglmayr et al. 2012). Thus, this isolate is classified under a novel genus, Pseudomelanconiella.