First record of the genus Gratia Thomas (Ephemeroptera, Baetidae) from China with the description of a new species

A new species of Baetidae, Gratiabaibungensis sp. n., is described and illustrated based on nymphal stage collected from the southeastern Tibet (Xizang) and the genus is reported for the first time from China. This new species can be readily differentiated from its congeners by the absence of a protuberance on the posterior margin of the abdominal tergum X, glabrate simple submarginal setae on the labrum, and the posterior margin of sterna VI-IX having much longer spatulate setae.