Abstract / Introduction / Summary:
Postmetamorphic adult females of Lernaea cyprinacea Linnaeus, 1758 (Copepoda: Lernaeidae) were collected from medaka, Oryzias latipes (Temminck and Schlegel, 1846) (Beloniformes: Adrianichthyidae), in an irrigation ditch connecting with the Okoe River, a tributary of the lower Katada River (the Bansho River system), at Saeki, Oita Prefecture, Kyushu, southern Japan. This represents the first record of L. cyprinacea from Oita Prefecture. In two of the six individuals of L. cyprinacea collected, peritrich-like ciliates were heavily attached to the surface of the trunk. Based on the literature published between 1935 to 2020, 21 nominal species of metazoan parasites (16 trematodes, one cestode, two nematodes, one branchiuran, and one copepod) have been reported from the prefecture.