A taxonomic revision of <i>Aureobasidium</i> (<i>Saccotheciaceae</i>, <i>Dothideales</i>) with new species, new names, and typifications

<i>Aureobasidium</i> comprises dimorphic yeast-like fungi that usually produce melanised cells at maturity. Species are globally distributed and ubiquitous, colonizing a variety of habitats. At present, ca 40 species are accepted, with the type, <i>A. pullulans</i>, representing a complex of unresolved cryptic species. In this study, we isolated 128 <i>Aureobasidium</i> from multiple temperate and tropical regions. We performed multigene analyses using eight loci (ITS, 28S, <i>EF1a</i>, <i>ELO2</i>, <i>RPB2</i>, <i>BTUB</i>, mtLSU and mtSSU) on new isolates and including sequences from type material for all available <i>Aureobasidium</i> species. Data on growth, physiological profiles, micro- and macromorphological attributes were also collected and analysed. Several DNA-based species delimitation methods were evaluated for their ability to delimit species. We found that assimilation of D-quinic acid, L-sorbose, D-mannitol, gluconolactone, erythritol, L-arabinose, and sodium succinate dibasic hexahydrate were important in delineating species of <i>Aureobasidium</i> and note that production of pigmentation in culture often takes longer than the 14 d standard for carbon assimilations. Genealogical concordance phylogenetic species recognition criteria (GCPSR) provided the most consistent results for species delimitation. We describe nine new species of <i>Aureobasidium (A. albui</i>, <i>A. cavalettoi</i>, <i>A. diazvalderramae</i>, <i>A. ellingtonae</i>, <i>A. essambei</i>, <i>A. peruvianum</i>, <i>A. rubi</i>, <i>A. toomeae</i>, and <i>A. vanuatuense</i>), make new combinations for <i>A. aubasidani</i> (<i>≡ A. pullulans</i> var. <i>aubasidani</i>), <i>A. fermentans</i> (<i>≡ Pullularia fermentans</i>), and <i>A. mahoniae</i> (<i>≡ Selenophoma mahoniae</i>), validate and provide descriptions for <i>A. musti</i> and <i>A. uvarum</i>, and provide lecto- and epitypes for <i>Dematium pullulans</i>, the basionym of <i>A. pullulans.</i> Finally, we resolved the phylogeny for <i>Aureobasidium</i>, reduce <i>Kabatiella</i> (based on <i>K. microsticta</i>) to synonymy, and provide an updated list of species to facilitate future studies. <b>Citation:</b> Jumbam B, Zasada IA, Bensch K, Crous PW, Aime MC (2025). A taxonomic revision of <i>Aureobasidium</i> (<i>Saccotheciaceae</i>, <i>Dothideales</i>) with new species, new names, and typifications. <i>Persoonia</i> <b>54</b>: 147-195. doi: 10.3114/persoonia.2025.54.05.