Unveiling Species Diversity Within Early-Diverging Fungi from China VIII: Four New Species in Mortierellaceae (Mortierellomycota)

The fungal family Mortierellaceae represents ubiquitous and ecologically significant components of soil ecosystems across terrestrial habitats. Through an integrative taxonomic approach combining multi-locus phylogenetic analyses (ITS, LSU, SSU rDNA, RPB1, and Act) with detailed morpho-logical examinations of rhizosphere soil isolates, four novel species within this family were pro-posed. This study describes and illustrates these taxa, elucidating their morphological distinctions from allied species and phylogenetic relationships within the family. Linnemannia rotunda sp. nov. (closely related to L. longigemmata) is distinguished by its globose sporangia and sporangiospores. Mortierella acuta sp. nov. is characterized by spiky collarettes. Mortierella oedema sp. nov. (a sister to M. macrocystis) exhibits distinctive ampulliform swellings. Mortierella tibetensis sp. nov. (clustering with M. parvispora), named for its geographic origin in Tibet. As the eighth installment in a sys-tematic investigation of early-diverging fungal diversity in China, this work expands the global taxonomic inventory of Mortierellaceae to 148 species, underscoring the ongoing discovery of cryptic biodiversity within this ecologically pivotal group.