Prototaria is an extinct genus of pinniped that lived approximately 15.97 to 13.65 mya[1] during the Middle Miocene in what is now Japan.

[2] Unlike their closest living relative, the walrus, members of Prototaria were primarily piscivorous carnivores.

Prototaria were more similar in appearance to modern fur seals and sea lions than walruses.

Fossils ascribed to Prototaria exhibit some autapomorphies, including: a large antorbital process and orbit, and a relatively narrow intertemporal region of the skull.

[2] P. planicephala has a wider rostrum than P. primigena as well as more specialized cheek teeth and a flatter tympanic bulla.