Recent molecular evidence suggests that pinnipeds evolved from a bearlike ancestor about 23 million years ago during the late Oligocene or early Miocene epochs, a transitional period between the warmer Paleogene and cooler Neogene period.
The continental sandstones and siltstones of the Abu Zenima Formation represent the earliest syn-rift deposits of late Oligocene (Chattian) to early Miocene (Aquitanian) age.