The world’s first exhibit of the crab Poupinia hirsuta, second record of the species in Japan

Okinawa Churaumi Aquarium announces the world’s first exhibit of the crab Poupinia hirsuta.

≪ケブカミズヒキガニ≫
Scientific name：Poupinia hirsuta

　This species of Homoloidea crab inhabits the Society Islands, North Mariana Islands and Okinotori Islands at depths from 366 to 600 meters. This is an extremely rare species, only one individual had been previously found in Japanese waters. The crab’s Japanese name was suggested in 2019 based on the individual caught south of the Okinotori Islands.

Its appearance from the front
Its appearance from the rear
(The arrows point to its fourth pair of long elongated walking legs)

　For this exhibit the individual was given to Churaumi Aquarium by the Okinawa pref. Deep sea water Research Center on Kume Island in July 2024. It was confirmed as Poupinia hirsuta by observing that it had no pair of lines present on the dorsal carapace, its fourth legs were long and elongated and the tips were not scissor-shaped. (The depth of the water intake installation at the Okinawa pref. Deep sea water Researchs Center is 612 meters.)

Place of exhibit

Okinawa Churaumi Aquarium "Small Life in the Deep Sea"

Exhibit duration

July 15th 2024～
*Exhibit may close depending on the condition of the animals.

Number of exhibit

1 individual (carapace width 50mm)

　Generally, the Homoloidea superfamily of the Dromiacean crabs are known to use their fourth walking legs to collect sponges and carry them on their backs for camouflage. However, while rearing and observing this individual, it did not use its fourth walking legs to collect anything, nor did it carry anything on its back. It did not even use its fourth legs to walk. At this point, for this species, we are not sure of the purpose of this fourth pair of walking legs.
At our facility we shall continue to discover more about the ecology of this crab species through rearing.