Pararoussoella coffeae L. Lu & Tibpromma 2025, sp. nov.

Pararoussoella coffeae L. Lu & Tibpromma sp. nov. Fig. 18 Etymology. The species epithet “ coffeae ” refers to the host plant genus “ Coffea ” from which the fungus was isolated. Diagnosis. Differs from other Pararoussoella species by the subcylindrical to ellipsoid or, sometimes, ovoid conidia. Holotype. HKAS 137609. Description. Saprobic on decaying branch of C. arabica. Teleomorph: Not observed. Anamorph: Conidiomata 60–120 µm high × 100–160 µm diam. (x- = 92 × 121 µm, n = 15), pycnidial, immersed, globose to subglobose, brown, with central ostioles. Conidiomatal wall 15–25 µm wide (x- = 19 µm, n = 20), hyaline to light brown, thick, 4–6 layers, outer layer composed of brown cells of textura angularis, lined with a hyaline layer bearing conidiogenous cells. Conidiophores inconspicuous or micronematous, often reduced to conidiogenous cells. Conidiogenous cells lining the inner cavity, hyaline, smooth, oval to obpyriform or doliiform, phialidic with periclinal thickening at apex, 3–5 × 2–5 µm (x- = 4 × 3.5 µm, n = 30). Conidia 3.5–5 × 2–3 µm (x- = 4.4 × 2.4 µm, n = 30), aseptate, solitary, guttulate, subcylindrical to ellipsoid or, sometimes, ovoid, smooth, apex bluntly rounded, base truncate, hyaline when young, becoming light brown when mature. Culture characteristics. Conidia germinating on PDA within 24 h, colonies reached 2.5–3 cm in diameter after one month at 25 ° C, filamentous, with entire margin, flat to raised, with many white aerial mycelia, from above, white at the centre, yellowish at the edge, from below, yellowish. Materials examined. China, Yunnan Province, Lincang, on a decaying branch of Coffea arabica (Rubiaceae) (24°17'N, 99°99'E, 960 m alt.), 28 July 2022, LiLu, LC 1 - C 3 (HKAS 137609, holotype), isotype MHZU 23-0061, ex-type living culture KUNCC 24-18355 = KUNCC 24-18356, ex-isotype living culture ZHKUCC 23-0632 = ZHKUCC 23-0633. Notes. In the concatenated phylogenetic analysis, Pararoussoella coffeae forms a sister branch basal to P. mangrovei (Phukhams. & K. D. Hyde) Phukhams. & K. D. Hyde (Fig. 19). Since P. mangrovei has only been reported as teleomorph, we performed nucleotide comparisons; P. coffeae (ZHKUCC 23-0632) is different from P. mangrovei (MFLUCC 16-0424) by 20 / 434 bp (4.6 %, without gaps) of the ITS, 14 / 805 bp (1.7 %, without gaps) of the LSU, 99 / 796 bp (12 %, without gaps) of the RPB 2 and 28 / 718 bp (3.8 %, without gaps) of the TEF 1 - α. Based on morphology, our novel taxon in Pararoussoella is similar to the species P. juglandicola Crous & R. K. Schumach. in aseptate and brown conidia, but differs in the shape of conidia. The conidia of our new species are subcylindrical to ellipsoid, sometimes ovoid, while the conidia of P. juglandicola are subcylindrical; besides, the characteristics of guttulate in our species are more distinct than P. juglandicola (Fig. 18; Crous et al. (2019)). In addition, the PHI test results (Fig. 22 i) revealed no significant recombination relationships between P. coffeae and its phylogenetically related taxa. Therefore, the morphological differences and phylogenetic analyses support the introduction of P. coffeae as a new species.