Taxonomy, phylogeny, and evolutionary diversification of spider-pathogenic fungi from China (Hypocreales, Ascomycota)

Spider-pathogenic fungi serve as critical regulators of spider populations in natural systems, playing irreplaceable roles in maintaining ecological balance and also serving as reservoirs of bioactive compounds. Despite recent taxonomic refinements at the generic level, their broader phylogenetic diversity remains significantly underrepresented compared to entomopathogenic fungi. In this study, we collected several novel spider-pathogenic fungi from various provinces in China and conducted comprehensive taxonomic and phylogenetic analyses.

Based on integrated morphological characterization and multigene phylogenetic analyses of five loci (ITS, nrLSU, TEF 1, RPB 1, and RPB 2), eight novel species are described and illustrated: Arachnidicola (1), Gamszarella (1), Gibellula (2), Hevansia (1), and Liangia (1) within Cordycipitaceae; Husseyia (1) within Clavicipitaceae; and Purpureocillium (1) within Ophiocordycipitaceae. Additionally, six new combinations are proposed, one Chinese new record is reported, the type specimen of one known species is revised, and five potential cryptic species are identified.

Our phylogenetic analyses provide robust evidence for the taxonomic placement of Chlorocillium and Husseyia within Clavicipitaceae. Molecular clock analysis, utilizing a dataset of five loci from 648 fungal strains, estimated the stem and crown ages of Hypocreales and indicated that spider-pathogenic fungi likely emerged during the mid-Cretaceous and subsequently diversified. Multiple lineages displayed marked trends toward host specialization, suggesting that these fungi developed highly efficient parasitic strategies to exploit constrained ecological niches.

This research substantially expands the documented diversity of araneopathogenic fungi, providing a robust phylogenetic framework for elucidating their evolutionary origins and diversification patterns, while offering valuable biological resources for future biotechnological and ecological applications.