A review of Chinese Prosopistomatidae with a description of the first Asian <italic>Prosopistoma</italic> imago of a new species (Insecta: Ephemeroptera)

Previously, no adult of the Asian Prosopistomatidae had been reported despite that this region has over half species of the family. Similarly, while six species have been discovered in China, they have never been systematically compared. In this study, we provide detailed photos of all Chinese Mainland species, including a new one named <italic>Prosopistoma wuchang</italic> sp. nov. In nymphs, the new species has a flat body and a distinct carapace color pattern. In adults, it exhibits clear sexual dimorphism in both color and structure. Males can be recognized by unnotched posterior flange of imaginal head, U-shaped median notch of imaginal penes and hooked claw of subimagos. Females can be recognized by uniformly brown body, non-branching veins of hindwings, postero-lateral projections of abdominal segments and the white filament arising from mesonotum. Taxonomically, this new species represents the first known adult from Asia and the first nymph-adult association via molecular sequences. Biologically, the nymphs of this new species live in the rapid currents of a wide river in southwestern China, while the adults emerge at dawn. [ABSTRACT FROM AUTHOR]