Phylogeny and taxonomic revision of Microascaceae with emphasis on synnematous fungi.

The taxonomy of the synnematous genera Cephalotrichum, Doratomyces and Trichurus, and other related genera Gamsia, Wardomyces and Wardomycopsis, has been controversial and relies mainly on morphological criteria. These are microascaceous saprobic fungi mostly found in air and soil and with a worldwide distribution. In order to clarify their taxonomy and to delineate generic boundaries within the Microascaceae, we studied 57 isolates that include clinical, environmental and all the available ex-type strains of a large set of species by means of morphological, physiological and molecular phylogenetic analyses using DNA sequence data of four loci (the ITS region, and fragments of rDNA LSU, translation elongation factor 1α and β-tubulin). The results demonstrate that Cephalotrichum, Doratomyces and Trichurus are congeneric and the genus Cephalotrichum is accepted here with Echinobotryum as a further synonym. The genera Acaulium and Fairmania, typified by A. albonigrescens and F. singularis, respectively, are distinct from Microascus and Scopulariopsis, Gamsia is distinct from Wardomyces, and Wardomycopsis is confirmed as a separate genus in the Microascaceae. Two new species of Cephalotrichum are described as C. brevistipitatum and C. hinnuleum. Nine new combinations are proposed, i.e. Acaulium acremonium, A. caviariforme, Cephalotrichum asperulum, C. columnare, C. cylindricum, C. dendrocephalum, C. gorgonifer, Gamsia columbina and Wardomyces giganteus. A neotype is designed for C. stemonitis. Lectotypes and epitypes are designated for A. acremonium, A. albonigrescens, C. gorgonifer, C. nanum and W. anomalus. Cephalotrichum cylindricum, C. microsporum, F. singularis and Gamsia columbina are also epitypified with new specimens. Descriptions of the phenotypic features and dichotomous keys for identification are provided for accepted species in the different genera.