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Four species of the genus Cunina, C. duplicata, C. peregrina, C. globosa and C. octonaria, have been reported from Japanese waters. However, some of species still unidentified. In this study, six specimens of an unidentified Cunina species collected from Kochi, Nagasaki and Okinawa prefectures were examined by morphological observations. The present study reports detailed observations of the morphology of one species newly recorded in Japan: Cunina simplex. This species possesses the following unique morphological characters: four manubrial pouches and four primary tentacles. This study reported C. simplex as the fifth described species from Japan. [ABSTRACT FROM AUTHOR]

We surveyed the spatial and temporal distribution of Japanese sea nettle jellyfish Chrysaora pacifica in Omura Bay, Japan, using an environmental DNA (eDNA) method. In 2018, the C. pacifica eDNA concentration increased from March-May at all depths. The seasonal pattern of C. pacifica eDNA was consistent with previous reports based on visual observations along the Japanese coast. Thus, the eDNA method might have advantages to follow the seasonal pattern of C. pacifica while being less time-consuming and less laborious compared with traditional methods. The eDNA concentrations tended to reach a maximum near and/or below the pycnocline throughout this study. Therefore, the vertical distribution of C. pacifica medusae may have been restricted by strong pycnocline formation in July and August 2018. However, even with a weak pycnocline, which C. pacifica should be able to swim across, the apparent distribution of C. pacifica eDNA seems to be restricted by the pycnocline. Therefore, the eDNA method cannot, currently, accurately assess the absolute vertical distribution pattern of C. pacifica, especially when a pycnocline is formed. [ABSTRACT FROM AUTHOR]