Tolypocladium, a diverse genus of fungicolous fungi belonging to Ophiocordycipitaceae, includes saprotrophic soil inhabitants, plant endophytes and pathogens of insects, nematodes, rotifers, and parasites of truffle-like fungi. Here, we review the research progress achieved for Tolypocladium regarding its taxonomy, species diversity, geographic distribution, host affiliations and ecological diversity. Furthermore, an undescribed taxon from China was established using morphology and multi-gene phylogeny. Tolypocladium inusitaticapitatum is introduced as a new species parasitizing ectomycorrhizal Elaphomyces species. It is diagnosed by its irregularly enlarged fertile heads and lemon, yellow-to-dark-brown, smooth and nearly cylindrical stipe. Phylogenetic analyses based on SSU, LSU, ITS, TEF1-α and RPB2 sequence data showed T. inusitaticapitatum to be an independent lineage separated from T. flavonigrum in the clade comprising T. capitatum, T. fractum and T. longisegmentatum. A key for identifying the sexual Tolypocladium species is also provided.
