Imagotaria downsi

Imagotaria downsi is the only species of the extinct walrus genus Imagotaria, whose fossils come from the early late Miocene, about 10 to 12 million years ago, of California and also from Fukushima Prefecture in Japan. The animal was about 1.8 metres long and looked more like a sea lion than a walrus. It did not have the elongate, ever growing tusks of the living walrus but bore enlarged canines compared with other pinnipeds. Its conical, unworn teeth and the lack of a vaulted palate show that it did not feed on molluscs as the modern walrus does. Fossils of Imagotaria show that early walruses already had extreme sexual dimorphism, with males and females of very different size.