Three specimens (31.6–38.2 mm standard length) of Cypho zaps Gill, 2004 (Pseudochromidae), previously known from voucher specimens only from Indonesia, the Philippines, and southern Taiwan, were collected off Yonaguni-jima island, Yaeyama Islands, southern Ryukyu Islands. They were clearly distinguished from the only known other congener, C. purpurascens (De Vis, 1884), by the staggered arrangement of the dark vertical lines in the center of each body scale, which do not form continuous bars as they do in the latter species. These specimens represent the first records of C. zaps from Japan supported by voucher specimens, and the northernmost distributional records of the species.
We are especially grateful to T. Uchiyama (Diving Service MARLIN) for his help in the field survey and for providing an underwater photograph. We thank K. Eguchi, T. Inaba, and T. Uejo (KAUM); Y. Kimura, S. Tanaka, and M. Fujisawa (Hiroshima University); Y. Hibino, D. Sasaki, T. Furukawa, and H. Suzuki (Mie University); R. Miki and H. Wada (University of Miyazaki); and T. Kunishima and M. Sakurai (University of the Ryukyus) for their help in field collection and examination of specimens, and G. Hardy (Ngunguru, New Zealand) for reading the manuscript and providing help with the English. We also thank H. Senou (KPM) for the opportunity to examine underwater photographs. This study was supported in part by a Grant-in-Aid from the Japan Society for the Promotion of Science, Tokyo, Japan (JSPS) to JSPS Fellows (PD: 26–477) to the second author, plus Grants-in-Aid for Scientific Research (A: 26241027, B: 24370041, and C: 23580259 and 26450265) from JSPS; the JSPS Core-to-Core Program, “Research and Education Network on Southeast Asian Coastal Ecosystems”; the “Coastal Area Capability Enhancement in Southeast Asia Project” of the Research Institute for Humanity and Nature, Kyoto, Japan; the “Biological Properties of Biodiversity Hotspots in Japan” project of the National Museum of Nature and Science, Tsukuba, Japan; and the “Establishment of Research and Education Network on Biodiversity and Its Conservation in the Satsunan Islands” project of Kagoshima University adopted by the Ministry of Education, Culture, Sports, Science and Technology, Japan.