Archaeodobenus akamatsui

Archaeodobenus akamatsui is an extinct relative of the walrus that lived in what is now Japan during the Late Miocene. The Japanese palaeontologists Yoshihiro Tanaka and Naoki Kohno named it in 2015 from a partial skull, vertebrae and limb bones collected in 1977 from the Ichibangawa Formation in Tobetsu Town on the island of Hokkaido. The genus name means ancient walrus, and the species name honours Morio Akamatsu, a curator of the Hokkaido Museum. Unlike the modern walrus it had no tusks, only canines of moderate size, and it looked more like a sea lion. The holotype appears to have been a young adult male about 3 metres long that weighed roughly 473 kilograms.