Morphological and molecular characterization of the new aethaloid species <i>Didymium yulii</i>

Five specimens, initially presumed to be <i>Fuligo septica</i> or <i>Mucilago crustacea</i>, were collected from Jilin Province and the Inner Mongolia Autonomous Region in China, but all five turned out to represent a new aethaloid species, <i>Didymium yulii</i>. This new species is characterized by pseudocapillitia without capillitia and an aethalioid fruiting body, features that are morphologically distinct from those of any other species of <i>Didymium</i>. To assess the phylogenetic relationships between <i>D. yulii</i> and other members of <i>Didymium</i> and in the Didymiaceae, sequences from two nonoverlapping targeted portions of nuc 18S rDNA (~450 bp and ~1050 bp) and translation elongation factor 1-alpha (<i>tef1</i>) were obtained and analyzed. The results indicate that <i>D. yulii</i> forms a single clade separate from other species of <i>Didymium</i> and the clade that contains <i>M. crustacea</i>, which strongly supports the identification of the five specimens as a new species.