Jurassic larvae of mayflies (Ephemeroptera) from the daohugou formation in inner mongolia, China

Two mayfly larvae from the Callovian or Oxfordian (uppermost Middle Jurassic or lowermost Upper Jurassic) Daohugou Formation in Inner Mongolia, China are described as Fuyous gregarius, gen. et sp. nov. (family Fuyoidae, fam. nov.) and Shantous lacustris, gen. et sp. nov. (family Hexa-genitidae). These larval forms were previously identified as Mesoneta antiqua Brauer, Redtenbacher & Ganglbauer, 1889 and Mesobaetis sibirica Brauer, Redtenbacher & Ganglbauer, 1889, respectively. The both Lower Jurassic species Mesoneta antiqua and Mesobaetis sibirica lack not only in the Daohugou Formation, but elsewhere in China. The taxonomic placements of all the mayfly records earlier from the Mesozoic of China are questionable, and are briefly reviewed and reassessed.