抄録
Two specimens of Diadema setosum (Leske, 1778) were collected from Onahama Port, Tatsumi-cho, Onahama, Iwaki, Fukushima Prefecture, Japan, on August 15, 2024. This represents the first record of diadematid sea urchin in Fukushima Prefecture and also appears to be the northernmost record of the species. In this report, the external morphology of D. setosum was described in detail based on the collected specimens. Diadema setosum is a tropical to subtropical species distributed in the Indo-West Pacific Ocean. Therefore, continuous research is needed to determine whether the occurrence of these tropical-subtropical animals is due to long-term seawater temperature increase or a temporary effect of warm currents.
https://ror.org/057zh3y96 
