Meliola fuscobrunnea Khan M. B. & T. C. Wen, 2025

Meliola fuscobrunnea Khan M. B. & T. C. Wen sp. nov.

Fig. 2 View Figure 2

Etymology.

From Latin, “ fusco ” meaning “dark,” and “ brunnea ” meaning “brown,” referring ” to the distinct dark brown color of Ascospores.

Diagnosis.

Appressoria small and variable in size and slightly thick; ascomata superficial and relatively small; setae moderately long, straight to slightly curved with well-developed, clearly visible phialides; ascospores cylindrical or oblong and comparatively large, and dark brown in color.

Holotype.

China • Yunnan Province, Gaoligong Mountains, Muhammad Binyamin Khan , 27 July 2024, HKAS 146650 View Materials , GenBank accession numbers PV 299283 (SSU) and PV 298265 (LSU).

Additional materials examined.

China • Yunnan Province, Gejia Mountain, Muhammad Binyamin Khan , 26 July 2024, HKAS 146649 View Materials , GenBank accession numbers PV 298266 (SSU) and PV 298264 (LSU) .

Habitat.

On leaving leaves of Annona squamosa .

Description.

Biotrophic on the surface of living leaves of A. squamosa . Colonies 5–10 mm in diameter, epiphyllous, scattered, black. Hyphae superficial, black, straight to substraight, branched, septate, each cell 19–21 μm long (x ̄ = 20 μm, n = 20), reticulate with dark brown setae. Hyphal setae up to 305 μm long, subdense, dark brown, straight to curved, 2 - dentate, obtuse. Appressoria 8–18 × 4–11 μm (x ̄ = 13 × 7 µm, n = 30), 2 - celled, brown, clavate, straight to curved, formed near the septa, unilateral, antrorse. Sexual morph: Ascomata up to 200 μm in diameter, superficial, subdense, dark, globose to subglobose, with a central ostiole. Peridium comprises hyaline inner cell and dark brown outer wall with textura angularis. Hamathecium with evanescent paraphyses. Ascospores 46–52 × 14–18 μm (x ̄ = 49 × 16 µm, n = 20), 2–3 seriate, cylindrical or oblong, hyaline when young, becoming dark brown when mature, 4 - septate, constricted at the septa, rounded at both ends, smooth-walled. Asexual morph: Phialides 17–25 × 5–9 μm (x ̄ = 21 × 77 µm, n = 10), opposite to unilateral, flask-shaped, mixed with appressoria, ampulliform.

Notes.

Meliola fuscobrunnea ( HKAS 146649 , HKAS 146650 ) forms a strongly supported clade with M. clerodendri-infortunati ( MFLU 13-0624 , MFLU 16-0069 ) with high statistical support (MLBS 99 %) (Fig. 1 View Figure 1 ). Both species have similar orientation and arrangement of superficial hyphae, hyphal setae length, appressorium colour and position, ascomata shape, and peridium wall colour. Meliola clerodendri-infortunati is distinct from M. fuscobrunnea in hyphal setae apex and size of appressorium, ascomata, and ascospore. Additionally, the two species also differ in host association, with the former found on Clerodendrum infortunatum L. and the latter on A. squamosa ( Hyde et al. 2017) . Hence, based on the differences in morphological characteristics, phylogenetic analyses, and host differences, we introduce M. fuscobrunnea as a new species of Meliola .