Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum Vol. 53, No. 1

On Ergaea walshi (Reeve) (Littorinimorpha: Calyptraeidae) preserved in gastropods from the PliocenePleistocene of Japan

Hiroaki Karasawa, Motohiro Kawase, Takahisa Goda, and Nobuaki Kobayashi

Published: 2026/2/20   Page: 29–31

Ergaea walshi (Reeve), a symbiotic calyptraeid inhabits inside of gastropod shells used by hermit crabs. We report E. walshi preserved in gastropods from the Upper Pliocene–Lower Pleistocene (Piacenzian–Gelasian) Takanabe Formation and the Middle Pleistocene Toyohashi Formation. These autochthonous occurrences of E. walshi are an exceptional fossil record from the Pliocene–Pleistocene of Japan.