Three new entomopathogenic fungi (Hypocreales, Cordycipitaceae) in Fodingshan Nature Reserve, Guizhou, China.

During a survey of entomopathogenic fungi in Guizhou's Fodingshan Nature Reserve, three new Cordycipitaceae species - Arachnidicola fodingshanensis sp. nov., Simplicillium fodingshanense sp. nov., and S. shiqianense sp. nov.-were discovered and described. Arachnidicola fodingshanensis, isolated from a dead spider, forms a clade with A. kanyawimiae and A. sinensis, but distinguishable by its longer phialides and ovoid to ellipsoidal conidia in culture. The nucleotide base comparison demonstrates that the species slightly differs from A. kanyawimiae, whereas greater divergence is observed from A. sinensis (1.56% in ITS, 0.79% in LSU, 3.87% in rpb2, and 0.91% in tef-1α). Simplicillium fodingshanense (isolated from a lepidopteran cocoon) and S. shiqianense (isolated from a dead spider) both cluster with S. subtropicum but form distinct, well-supported independent lineages (100% ML/1 PP). The interspecific nucleotide differences demonstrate that the species differ from related taxa by 1.03-1.54% in ITS, 0.25-0.90% in LSU, and 1.40-1.89% in tef-1α. Morphologically, S. fodingshanense is characterized by longer phialides than S. shiqianense and differs further in host association. The species is also readily distinguished from S. subtropicum by the absence of octahedral crystals, and by producing cylindrical to ellipsoidal conidia. In contrast, S. shiqianense is distinguished from S. subtropicum by its shorter phialides, the absence of both octahedral crystals and conidial slime head in culture, and its distinct host/substrate. The PHI test further supports genetic distinctness for Arachnidicola (Φw = 0.6876) and Simplicillium (Φw = 0.1587). Overall, these findings underscore the Fodingshan Reserve as a significant hotspot for fungal diversity and highlight the value of continued exploration in this underexplored karst region.