Three new species and a new record of cycloneuroterus (Hymenoptera: Cynipidae: Cynipini) inducing galls on cyclobalanopsis in Japan

The following three new species of Cycloneuroterus Melika et Tang (Hymenoptera: Cynipidae: Cynipini) from Japan are described: C. akagashiphilus from Quercus (Cyclobalanopsis) acuta and C. hisashii and C. arakashiphagus from Q. (C.) glauca. Quercus (C.) acuta is recorded as a host plant of Cynipini for the first time. Cycloneuroterus fortuitusus Tang et Melika, previously known from Taiwan, is newly recorded for Japan. A key to all eight recognized species of Cycloneuroterus is provided. The hitherto known five species of Cycloneuroterus were recorded in Taiwan only and four of them induce galls on the strictly Asian subgenus Cyclobalanopsis. Therefore, the discovery of the three new species of Cycloneuroterus in Japan confirms the close association between Cycloneuroterus and Cyclobalanopsis, and suggests the existence of the potentially diverse cynipid fauna on this subgenus in Asia. More extensive sampling is expected to reveal the species richness in the Cynipini in the region.