Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum No. 49

Discovery of the octopod predatory drill holes in the pectinid bivalve Kotorapecten egregius (Itoigawa, 1955) from the Akeyo Formation of the Mizunami Group in Mizunami City, central Japan

Yusuke Ando

Published: 2022/5/13   Page: 5158

Very small, stereotyped drill holes are found in 15 shells of Kotorapecten egregius (Itoigawa), collected from the lower Miocene Akeyo Formation (ca. 18 Ma) of the Mizunami Group in Mizunami City, Gifu, central Japan based upon the examination of the collection of Mizunami Fossil Museum. These drill holes can be assigned to the ichnotaxon Oichnus ovalis Bromley, attributed to predation by octopods. These examples are the oldest fossil records of the octopod-predatory drill holes found in Japan.