寄生鳞翅目幼虫的线虫草属一新种: 羽束梗孢状线虫草

Ophiocordyceps is a diverse, widely distributed, and host-rich genus of entomogenous fungi, with over 400 species reported to date. The Hengduan Mountains in Yunnan of southwestern China, recognized as a global biodiversity hotspot, represent a major center of diversity for this genus. In this study, we describe a new species of Ophiocordyceps from Hengduan Mountains in Yunnan, designated Ophiocordyceps paraisarioidea sp. nov., based on morphological observations and phylogenetic analyses using both single ITS sequences and a combined dataset of five loci (nrSSU, nrLSU, tef-1α, rpb1 and rpb2). Morphologically, this species is prone to misclassification as Paraisaria in virtue of stromatal structure, but it differs by having darker stromata, a spherical fertile part with apical protuberances, and multiseptate non-disarticulating ascospores. Five-gene phylogenetic analyses place O. paraisarioidea in the basal clade of Ophiocordyceps, clustering with Ophiocordyceps entomorrhiza. Nevertheless, the two species exhibit notable differences in morphology and host preference: O. paraisarioidea has dark brown stroma with grayish-white tips and parasitizes lepidopteran larvae, whereas O. entomorrhiza forms nearly black stromata and infects both larvae and adults of coleopteran insects (Carabus sp.). Notably, the lepidopteran host of O. paraisarioidea challenges the prevailing hypothesis that Coleopterans represent the ancestral hosts of Ophiocordyceps, implying the occurrence of multiple host shifts during the early evolutionary history. The discovery of O. paraisarioidea may provide valuable insight into the origin and early diversification of this genus.