I think Leviathan is more analogous to Tiamat, the Mesopotamian chaos dragon. Hinduism is far better at imagining dehumanizing, astronomical stretches of time with its vast cycles. Even if Leviathan were a dinosaur, that wouldn't amount to a dinosaurian eon that lasted for millions of years.

True, Yahweh himself is often rather reptilian in acting like a monstrous dinosaur. But you'd need to multiply that character in polytheistic fashion to arrive at the mind-shattering concept of a dinosaurian eon.