

undulatus was discovered in the Seto Inland Sea, Japan-namely, the Japanese sardinella Sardinella zunasi (Bleeker, 1854). Quite unexpectedly, in October 2019, a fish host of C. This copepod belongs to an intriguing group of congeners that, despite being part of a chiefly parasitic group, are consistently found as zooplankters. Until now, its fish host has remained unknown.

The siphonostomatoid copepod Caligus undulatus Shen & Li, 1959 has been widely reported from plankton samples obtained from neritic and oceanic waters off coasts of the Indo-West Pacific and Atlantic Oceans. 5 El Colegio de la Frontera Sur (ECOSUR), Unidad Chetumal, Chetumal, Mexico El Colegio de la Frontera Sur (ECOSUR), Unidad Chetumal Chetumal Mexico.4 Endangered Marine Species Research Unit, Borneo Marine Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia Endangered Marine Species Research Unit, Borneo Marine Research Institute, Universiti Malaysia Sabah Kota Kinabalu Malaysia.3 Graduate School of Science, Kobe University, Kobe, Japan Graduate School of Science, Kobe University Kobe Japan.2 Fisheries Science Laboratory, Setouchi Field Science Center, School of Applied Biological Science, Hiroshima University, Takehara, Japan Fisheries Science Laboratory, Setouchi Field Science Center, School of Applied Biological Science, Hiroshima University Takehara Japan.1 Fisheries Science Laboratory, Setouchi Field Science Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Takehara, Japan Fisheries Science Laboratory, Setouchi Field Science Center, Graduate School of Integrated Sciences for Life, Hiroshima University Takehara Japan.
