Expanding Lycogala: twenty-four new species, their morphology and phylogenetic relationships

The genus Lycogala was historically considered a small, morphologically uniform group of myxomycetes, with its classification remaining largely unchanged for most of the 20^th century. However, recent molecular studies have revealed exceptional cryptic diversity within the genus, challenging its traditional species delimitations. This study continues the taxonomic reassessment of Lycogala, integrating three-gene phylogenies and morphological analyses of 716 specimens from four continents. A total of 706 nucSSU, 273 mtSSU, and 130 COI sequences were analysed to delimit species within the genus using recombination test and distance-based delimitation. As a result, 716 specimens were assigned to 93 nucSSU ribogroups, which were further grouped into 63 putative morphological species. Of these, only 20 had been formally described prior to this study. Herein, we describe an additional 24 species, significantly expanding the known diversity of the genus. Phylogenetic analyses suggest the division of Lycogala into five major clades, which correspond to distinct morphological traits, supporting the proposal of five new sections within the genus. The study also confirms that L. epidendrum s. str. exhibits significant genetic polymorphism, with at least 29 subgroups detected. However, species delimitation within L. epidendrum remains challenging due to conflicting results from genetic markers and the presence of recombined genotypes. The study underscores the necessity of integrating molecular and morphological approaches for resolving Lycogala taxonomy and highlights the potential for further discoveries in myxomycete diversity. Citation: Leontyev D, Ishchenko Y, Leontieva M, Yatsiuk I, Shchepin O, Song W-L, Chen SL, Moroz E, Schnittler M (2025). Expanding Lycogala: twenty-four new species, their morphology and phylogenetic relationships. Fungal Systematics and Evolution 16: 93-146. doi: 10.3114/fuse.2025.16.7.