Moelleriella cinnamomum X. L. Xu & C. L. Yang 2025, sp. nov.

Moelleriella cinnamomum X. L. Xu & C. L. Yang sp. nov. Fig. 8 Etymology. In reference to the generic name of host plants. Diagnosis. Similar to Moelleriella simaoensis, M. puerensis, M. raciborskii, and M. citrus, M. cinnamomum differs by having red-orange, thickened pulvinate stromata, longer conidia and paraphyses, and the absence of a hypothallus surrounding the stroma. Type. CHINA • Sichuan Province, Chengdu City, Chongzhou County. Infected scale insects were found on the underside of leaves of Cinnamomum cassia (L.) D. Don., 30°48.82'N, 103°31.52'E, alt. 851 m, 1 May 2021, C. L. Yang, YCL 202105001 (SICAU 25-0086 – holotype preserved in the Herbarium of Sichuan Agricultural University; living culture SICAUCC 25-0067 – ex-holotype stored in the Culture Collection in Sichuan Agricultural University). Description. Parasitic on scale insects found on the underside of leaves of Cinnamomum cassia (Lauraceae). Sexual morph: Not observed. Asexual morph: Coelomycetous. Stromata red-orange in fresh specimens, mostly solitary, sometimes gregarious, globose to subglobose, thickened pulvinate up to 1 mm, 0.9–2.8 mm in diameter. Conidiomata aggregated in the center of the stroma and widely open, simple depressions of the surface without distinct rims. In section, conidioma flask-shaped or irregular, shallow. Conidial masses orange. Conidia hyaline, smooth, one-celled, fusoid, with acute ends, 13–16.5 × 2–3 µm. Paraphyses present, linear, filiform, up to 102 µm long. Culture characteristics. Conidia germinate in sterile water within 12 h, with germination tubes typically growing laterally from both ends of the spore and occasionally from the middle. Colonies on PDA at 25 ° C attaining 15 mm diameter in 20 days. Colonies pale yellow and formed compact pulvinate with abundant slimy masses. Conidial masses light yellow. Colonies reverse dark yellow with pale yellow margins. Conidia 9–15 × 1.8–2.8 µm. Paraphyses rare. Host. Scale insects (Coccidae). Habitat. Subtropical monsoon evergreen broad-leaf forests serve as the habitat for Moelleriella cinnamomum, which can infect scale insects found on the underside of Cinnamomum cassia leaves. Infections are typically observed throughout the trees, particularly in the lower canopy. Distribution. China, Sichuan Province, Chengdu City. Material examined. CHINA • Sichuan Province, Chengdu City, Chongzhou County. Infected scale insects were found on the underside of leaves of Cinnamomum cassia, 30°48'49.57"N, 103°31'31.19"E, alt. 851 m, 1 May 2021, C. L. Yang, YCL 202105001 (SICAU 25-0086, living culture SICAUCC 25-0067); • ibid. YCL 202105002 (SICAU 25-0087, living culture SICAUCC 25-0068). Notes. Our collections were nested in the Moelleriella clade related to M. citrus, M. raciborskii, M. simaoensis, M. hainanensis, M. puerensis, and M. pseudothanathonensis (Fig. 2). Morphologically, M. cinnamomum is distinct from the phylogenetically related six species, with red-orange and thickened pulvinate, while the other species are flattened and more pale in color (Liu et al. 2006; Chaverri et al. 2008; Wang et al. 2022 c, 2025; Yang et al. 2023 a). Moelleriella raciborskii, M. simaoensis, and M. puerensis can co-occur in the same stromata with both sexual and asexual morphs, whereas only the asexual morph of M. cinnamomum has been observed in stromatal tissue. Moelleriella hainanensis differs from M. cinnamomum by having larger stromata (3–4 mm vs. 0.9–2.8 mm), and along with M. raciborskii and M. citrus, it also differs by exhibiting a light-colored hypothallus surrounding the stroma. Conidia in M. cinnamomum (13–16.5 µm) are longer than those of M. simaoensis (8.8–14 µm), M. puerensis (9.7–13.4 µm), M. pseudothanathonensis (10–12.5 µm), and M. raciborskii (11–14 µm). Moreover, M. cinnamomum has longer paraphyses (up to 102 µm) than M. citrus (85–100 µm), M. simaoensis (up to 95 µm) and M. raciborskii (40–70 µm).