<i>Uwebraunomyces</i> , a novel genus of the family <i>Mycosphaerellaceae</i>

A hyaline to pale olivaceous brown hyphomycetous fungus was collected on living leaves of <i>Tinospora cordifolia</i> in India. Molecular phylogenetic analyses of several loci (LSU-<i>RPB2</i>-ITS) indicated a relationship with cercosporoid fungi (<i>Mycosphaerellaceae</i>). As no other known lineage shares similar morphology or DNA sequences, a new genus, <i>Uwebraunomyces</i>, is proposed, with <i>U. tinosporae comb. nov</i>. based on <i>Ramularia tinosporae</i> as the type species. Conidiophores are pale olivaceous to very pale brown in colour, typically unbranched, and subcylindrical to geniculate-sinuous at the tip. Conidia are solitary, obclavate to obpyriform, straight to curved, and few-septate. Additionally, the conidiogenous loci are characterized by a centrally located small papilla and a minute, distinct frill that is typically evident in older scars. These characteristics distinguish <i>Uwebraunomyces</i> from other closely related members of the ramularioid complex. Additionally, <i>Cercosporella bundelkhandae</i> is recognized as a new synonym as it shares nearly identical morphological features with <i>U. tinosporae</i>. At the ultrastructural level, <i>Uwebraunomyces</i> is further characterized by conidiogenous loci that bulge outward, forming convex or truncated cone shapes, with wall thickening extending beyond the area originally occupied by the base of the conidium. Older scars display a minute papilla or small, somewhat conical protuberant like structure in the centre of their apical depression, often accompanied by a minute, distinct frill. The conidial base is obconically truncate, featuring a basal depression with a centrally located, slightly protuberant structure. These distinct ultrastructural features set <i>Uwebraunomyces</i> apart from other members of the ramularioid complex, underscoring its taxonomic significance within the <i>Mycosphaerellaceae</i>. <b>Citation:</b> Singh G, Kumari P, Rajwar S, Yadav S, Mall S, Kumar S, Singh R (2025). <i>Uwebraunomyces</i>, a novel genus of the family <i>Mycosphaerellaceae</i>. <i>Fungal Systematics and Evolution</i> <b>16</b>: 197-214. doi: 10.3114/fuse.2025.16.11.