The parapagurid hermit crab, Paragiopagurus ventilatus, is reported from hydrothermal vents on the Nikko Seamount, Mariana Trough, at a depth of 410 m. This is the first record of this species outside Taiwan, and represents a major range extension. The animals were found using empty tubes of the siboglinid worm Lamellibrachia satsuma for housing, representing the first example of this carcinoecium for a hermit crab. However, it was observed that some of them changed their housing to gastropod shells during rearing in aquaria. Originally, this species was reported to use gastropod shells for housing. It is considered that the use of siboglinid tubes is due to necessity rather than preference, because empty gastropod shells are very scarce in the collection site.
