Two new species from tree-hole humus in Guizhou Province, China: Leptobacillium doupengense (Hypocreales, Cordycipitaceae) and Metapochonia doupengshanensis (Hypocreales, Clavicipitaceae)

Fungal strains were isolated from humus substrates collected from tree holes in Doupengshan Scenic Area, Duyun City, Guizhou Province, China, a region characterized by a typical karst ecosystem. Tree-hole humus represents a spatially restricted and nutrient-rich microhabitat formed by decomposed plant material and organic residues, yet hypocrealean fungi associated with this substrate remain poorly explored. Based on a combined five-gene dataset (ITS, nrSSU, nrLSU, tef - 1α and rpb1 ), together with phylogenetic analyses and morphological comparisons, two new species of Hypocreales were identified: Leptobacillium doupengense sp. nov . and Metapochonia doupengshanensis sp. nov . Both species formed distinct lineages in the phylogenetic tree and were clearly separated from other species within their respective genera. This study provides detailed morphological descriptions and illustrations of L. doupengense and M. doupengshanensis , along with comparisons with related species in their genera. The discovery of these two species highlights the potential of tree-hole humus in karst ecosystems as an overlooked source of hypocrealean fungal diversity. These findings provide morphological and molecular evidence for recognizing and distinguishing L. doupengense and M. doupengshanensis and contribute additional taxonomic data to clarify species diversity and phylogenetic relationships within Leptobacillium and Metapochonia .