New species Podoceropsis nanseiae discovered in Kagoshima Bay

The research group of Assistant Professor Masafumi Kodama, Graduate Student Yukiko Mukaida, Assistant Professor Fumihiro Makino, Associate Professor Takafumi Azuma of the Faculty of Fisheries at Kagoshima University, and Research Fellow Takuya Hosoki (Japan Society for the Promotion of Science Research Fellow PD) of the Field Science Center for Northern Biosphere at Hokkaido University, collected an undescribed species of the photid amphipods (a group of small crustaceans) from the seabed at a depth of about 100 meters in the mouth area of Kagoshima Bay during training cruise of the Nansei-maru in February 2023. The research group described this species as the new species Podoceropsis nanseiae Kodama, Mukaida, Hosoki, Makino & Azuma, 2024 (Japanese name: Nansei-sokoebi).

Kagoshima Bay is a valuable body of water with rich biodiversity owing to its deep volcanic waters, the Kuroshio branch current, and incoming rivers. The research group has conducted various training cruises and research activities in Kagoshima Bay and surrounding waters using Kagoshima University's training vessels Kagoshima-maru and Nansei-maru.

The photid amphipod collected by the research group in this study is about 7-mm long and has a beautiful appearance with a translucent light brown body color and reddish mottles. Detailed species identification indicated that it belonged to the genus Podoceropsis of the family Photidae. However, further examination revealed that it was an unknown species (undescribed species) with characteristics differing from those of any known species. Therefore, in a paper published in Plankton and Benthos Research, they described this photid amphipod as the new species Podoceropsis nanseiae Kodama, Mukaida, Hosoki, Makino & Azuma, 2024. The scientific name nanseiae is dedicated to Nansei-maru, a vessel that contributed to the collection. They also proposed the Japanese name "Nansei-sokoebi" after Nansei-maru.

The genome analysis in this study was made possible by the participation of Hosoki, a researcher affiliated with the Center for Field Science of the Northern Biosphere, through its Joint Usage/Education Center program. To describe this species, they sequenced the mitochondrial cytochrome c oxidase subunit I (COI) region, which is used for molecular phylogenetic analysis, DNA barcoding, and other purposes.

Many surveys have previously been conducted in Kagoshima Bay, where P. nanseiae was discovered in this study. It is likely that Kagoshima Bay houses many more unknown species. In particular, invertebrates with relatively small body sizes, such as P. nanseiae, have not been well studied. Further surveys of the Kagoshima Bay and surrounding waters may lead to the discovery of various new organisms.

Journal Information
Publication: Plankton and Benthos Research
Title: A new species of the genus Podoceropsis Boeck, 1861 (Crustacea: Amphipoda: Photidae) from Kagoshima Bay, Japan
DOI: 10.3800/pbr.19.141