Uncovering cryptic species diversity of Ophiocordyceps (Ophiocordycipitaceae) associated with Coleoptera from Thailand

Abstract

This study advances our understanding of Ophiocordyceps , an extensively studied entomopathogenic fungus within the Ophiocordycipitaceae , particularly in Thailand. We introduce seven novel species associated with Coleoptera – O. albostroma , O. brunnea , O. capilliformis , O. kohchangensis , O. phitsanulokensis , O. pseudovariabilis , and O. ratchaburiensis . Remarkably, O. brunnea , O. kohchangensis , and O. ratchaburiensis exhibit ascomata on the subterminal region of the stromata, with the asexual form appearing at the apex of the stipe, reminiscent of O. brunneipunctata . In contrast, O. phitsanulokensis produces its ascomata in the upper region of the stipe. Shared traits include immersed perithecia and part-spores production. Ophiocordyceps albostroma and O. pseudovariabilis produce pseudo-immersed perithecia, with the former producing ascospores breaking into four part-spores, and the latter displaying 32 part-spores. Ophiocordyceps capilliformis is also introduced due to morphological distinctions from closely related species. Phylogenetic analyses based on multigene loci (LSU, TEF1 , RPB1 , RPB2 ) robustly confirm the placement of these new species within Ophiocordyceps . Additionally, we report a new record of O. clavata in Thailand.