Taxonomy, phylogeny, and host associations of Petchiella and Sungia (Clavicipitaceae): Implications for the generic circumscription of Petchiella.

Fungi infecting mantid oothecae represent a highly specialized, long-overlooked group of entomopathogens in Hypocreales. The genus Petchia, previously erected for this lineage, is illegitimate as a later homonym of an Apocynaceae genus, and its members have recently been transferred to Petchiella. However, the diversity, host specificity, and generic boundaries of Petchiella and related clavicipitaceous pathogens remain poorly understood. In this study, we re-evaluated related taxa using multilocus phylogenetic analyses (ITS, nrSSU, nrLSU, tef-1α, rpb1, and rpb2) combined with detailed morphological characterization. Phylogenetic analyses showed that all mantid ootheca-associated isolates formed a strongly supported monophyletic lineage within Clavicipitaceae, closely related to a Petchiella species from hymenopteran pupal nests. Isolates from lepidopteran pupae formed an independent monophyletic lineage corresponding to the genus Sungia. We formally describe two new species and report one new geographical record. Petchiella longistipitata sp. nov., parasitic on mantid oothecae in China, is distinguished by elongated stromata (up to 3.2 cm long) and relatively short asci. Sungia puerensis sp. nov., pathogenic to lepidopteran pupae, differs from the type species S. yongmunensis by longer phialides (up to 48.8 μm) and larger conidia. Additionally, Petchiella siamensis is reported as a new record from the Mekong region of Southwestern China and northern Laos, with an updated morphological description based on newly collected mature specimens. The strict host specificity observed in these fungi, together with stable morphological differences and phylogenetic divergence, provides new evidence for the generic circumscription of Petchiella and ecological divergence within Clavicipitaceae. This study expands the known diversity of clavicipitaceous entomopathogens and provides foundational data for developing host-specific biocontrol agents against targeted insect pests.