New insights into freshwater ascomycetes: discovery of novel species in diverse aquatic habitats.

During investigations of freshwater fungi in Hunan and Yunnan provinces, China, sp. nov. (Nectriaceae), sp. nov. (Fuscosporellaceae), and sp. nov. (Pleurotheciaceae) were discovered on submerged decaying wood and branches. Based on phylogenetic analyses, formed a separate branch with and nested among other species in Nectriaceae (Hypocreales). Furthermore, hitherto known shared the same branch with , a type species of the genus, demonstrating their conspecific status. Therefore, is formally synonymized under , with an amended species circumscription. formed a well-separated subclade with the ex-type strain of and clustered with other within Fuscosporellaceae (Fuscosporellales). In addition, the genus is treated as distinct from due to a lack of phylogenetic evidence in clarifying their congeneric status with the latter. is found to be sister to , forming a subclade with within the Pleurotheciaceae (Pleurotheciales). Morphologically, fits well with the generic concept of in forming a holomorphic state with hyphomycetous asexual morph producing pigmented, setiform conidiophores, phialidic conidiogenous cells, hyaline conidia, and nectria-like sexual morph. fits well with in having acrogenous, apiosporous, versicolored, obovoid to obpyriform conidia. In contrast, resembles in forming asexual dimorphism with two types of conidia (Type I, brown, muriform/phragmosporous conidia; Type II, hyaline, amerosporous/didymorsporous conidia). The novelty of taxa is explained with detailed descriptions, photo-micrographic illustrations, polymorphism, and multigene phylogenetic analyses of Bayesian inference and maximum likelihood criteria.