Morphology, phylogeny and host specificity of two new Ophiocordyceps species belonging to the "zombie-ant fungi" clade (Ophiocordycipitaceae, Hypocreales)

Species of the genus Ophiocordyceps, which include species able to manipulate the behaviour of ants, are known as the "zombie-ant fungi" and have attracted much attention over the last decade. They are widespread within tropical, subtropical and even temperate forests worldwide, with relatively few reports from subtropical monsoon evergreen broadleaved forest. Fungal specimens have been collected from China, occurring on ants and producing hirsutella-like anamorphs. Based on a combination of morphological characters, phylogenetic analyses (LSU, SSU, TEF1a, RPB1 and RPB2) and ecological data, two new species, Ophiocordyceps tortuosa and O. ansiformis, are identified and proposed herein. Ophiocordyceps tortuosa and O. ansiformis are recorded on the same species of Colobopsis ant, based on phylogenetic analyses (COI), which may be sharing the same host. Ophiocordyceps tortuosa and O. ansiformis share the morphological character of producing lanceolate ascospores. They have typical characteristics distinguished from other species. The ascospore of O. tortuosa are tortuously arranged in the ascus and the ascospore of O. ansiformis have a structure like a handle-shape in the middle. Our molecular data also indicate that O. tortuosa and O. ansiformis are clearly distinct from other species.