Disentangling cryptic species with isaria-like morphs in Cordycipitaceae

ABSTRACTA new genus and eight new species, all with isaria-like phialides, are described in Cordycipitaceae from Thailand. The new genus, Samsoniella, is segregated from Akanthomycesbased on morphological and molecular evidence. Samsonielladiffers from Akanthomycesin producing orange cylindrical to clavate stromata with superficial perithecia and orange conidiophores with isaria-like phialides and white to cream conidia. A new combination for CBS 240.32, originally identified as Paecilomyces farinosus(Isaria farinosa), and CBS 262.58, originally identified as Penicillium alboaurantium, respectively, is made in Samsoniella. Two new species, Samsoniella aurantiaand S. inthanonensis, are described from lepidopteran larvae. Two new species of Cordyceps, C. blackwelliaeand C. lepidopterorum, were also found on coleopteran and lepidopteran larvae. Both produce isaria-like morphs with globose phialides and attenuated long necks and white mycelium in culture. The authors established a sexual-asexual link for Cordyceps javanica(= Isaria javanica) on lepidopteran larvae. Four new species, Akanthomyces kanyawimiae, A. sulphureus, A. thailandicus, and A. waltergamsii, were pathogenic on spiders, with some strains of A. kanyawimiaealso found on unidentified insect larvae. These four species of Akanthomycesoccur on the underside of leaves and produce white to cream white powdery conidia, whereas S. aurantiaand S. inthanonensiswere found in leaf litter and produce bright orange stromata and synnemata with white conidia. Another new combination, Akanthomyces ryukyuensis, is proposed. Phylogenetic analyses based on a combined data set comprising the nuc rDNA region encompassing the internal transcribed spacers 1 and 2 along with the 5.8S rDNA (ITS), nuc 28S rDNA (28S), partial sequences of translation elongation factor 1-α gene (TEF1), and the genes for RNA polymerase II largest (RPB1) and second-largest (RPB2) subunits strongly support the delimitation of these new species of Cordyceps, Akanthomyces, and in a new genus Samsoniellain Cordycipitaceae.