I used to think the lungfish was the halfway species between sea and land animals but I was not aware of the epaulette shark until the possible discovery of a new species of them made the news: Here is a five year old video:
According to the ABC news report they can stay out of water for up to two hours.
I can believe the part where they are said to survive on land by shutting down several of their brain functions. Now that might explain a lot about another, more familiar, two-legged creature that has become a land-dweller!