First contribution to the genera Branchiobaetis and Megabranchiella (Ephemeroptera, Baetidae) in China, with descriptions of two new species

<i>Branchiobaetis</i> Kaltenbach, Kluge & Gattolliat, 2022 and <i>Megabranchiella</i> Phlai-ngam & Tungpairojwong, 2022 (Ephemeroptera: Baetidae) are newly recorded in China. Two new species, <i>Branchiobaetisborealis</i> <b>sp. nov.</b> based on larval stage and <i>Branchiobaetismegasinus</i> <b>sp. nov.</b> based on larval and imaginal stages associated by laboratory rearing, are described. <i>Megabranchiellalongusa</i> Phlai-ngam & Tungpairojwong, 2022, previously only distributed from Thailand, is recorded from China for the first time.