抄録
Nemestheria aidaensis sp. nov. represents the first appearance in Japan of this genus, which is considered as the leading form of conchostracan fossils in nonmarine Cenomanian deposits and has a wide distribution. This new species is very similar to Nemestheria lineata Chang and Chen and Nemestheria robusta Zhang and Chen collected from the Qingshankou Formation of NE China. The results of both palaeontological researching and Fission-Track dating have shown that the Tsurukame Upper Formation of the Aioi Group might be Cenomanian in age.
