Moelleriella eucalypti X. L. Xu, Feng Liu & C. L. Yang 2025, sp. nov.

Moelleriella eucalypti X. L. Xu, Feng Liu & C. L. Yang sp. nov. Fig. 6 Etymology. In reference to the generic name of host plants. Diagnosis. Similar to Moelleriella sinensis in having somewhat similar stromata, M. eucalypti differs by having longer and wider paraphyses, shorter and wider conidiogenous cells, and wider conidia. Type. CHINA • Sichuan Province, Dazhou City, Heibaoshan National Forest Park. Infected scale insects were found on the underside of leaves of Eucalyptus sp. (Myrtaceae), 31°55.30'N, 107°47.75'E, alt. 690 m, 21 Jul. 2022, Feng Liu, LF 202207001 A (SICAU 25-0072 – holotype preserved in the Herbarium of Sichuan Agricultural University). Description. Parasitic on scale insects found on eucalyptus leaves. Sexual morph: Not observed. Asexual morph: Coelomycetous. Stromata yellow to dark orange in fresh specimens, pale yellow to white in old, entirely covering the insect hosts, thickened pulvinate, umbonate to hemispheric, cottony, sessile, globose to subglobose, tubercules on the surface, 1.5–2.5 mm in diameter, 1–2 mm in high. Conidiomata orifice scattered or circularly arranged, oval or elongate flask shaped, narrow orifices, 120–460 × 80–155 μm. Phialides hyaline, stick-shaped to cylindrical, 10–18 × 1–2.5 μm. Conidia hyaline, fusiform, yellow conidial masses, 8–12 × 1.5–3 μm. Paraphyses present, hyaline, filiform, 90–180 × 1.0–1.6 μm. Culture characteristics. No germination was observed due to the specimens being dried and the culture not being obtained. Host. Scale insects (Coccidae). Habitat. Subtropical monsoon evergreen broad-leaf forest. Scale insects were infected on the underside of eucalyptus leaves. Distribution. China, Sichuan Province, Dazhou City. Material examined. CHINA • Sichuan Province, Dazhou City, Heibaoshan National Forest Park. Infected scale insects were found on the underside of leaves of Eucalyptus sp., 31°55.30'N, 107°47.75'E, alt. 690 m, 21 Jul. 2022, Feng Liu, LF 202207001 A (SICAU 25-0072); • ibid. LF 202207001 B (SICAU 25-0073); • ibid. LF 202207001 C (SICAU 25-0074); • ibid. LF 202207001 D (SICAU 25-0075). Notes. Phylogenetically, our collections are closely related to Moelleriella sinensis, showing few sequence differences with the type strain CGMCC 3.18911, specifically 1 bp in LSU (0.12 %, 0 gap) and 8 bp in rpb 1 (1.10 %, 0 gap), while the tef 1 - α sequence is invalid. Moelleriella sinensis was first described on whitefly nymphs (Hemiptera) and later found on scale insects (Coccidae) in Thailand (Chen et al. 2020; Khonsanit et al. 2021). The described specimens of M. sinensis are primarily characterized by flat to umbonate, pale yellow pulvinate stromata and fusiform conidia. However, our collections differ from M. sinensis in having pulvinate stromata that are yellow to dark orange when fresh, pale yellow to white when old, and thicker in appearance. Additionally, they have longer and wider paraphyses (90–180 × 1.0–1.6 μm vs. 43.2–68.9 × 0.6–0.8 μm), shorter and wider conidiogenous cells (10–18 × 1–2.5 μm vs. up to 30 μm × 0.8–1.3 μm), and wider conidia (1.5–3 μm vs. 1.3–1.8 μm). Hence, we introduce M. eucalypti as a new species, based on the distinct morphological differences observed.