Nearly 400 million years ago, an unusual group of fish gave rise to the first land-dwelling vertebrates. Since then, their descendants have repeatedly moved back into the water. This episode, we explore the many ways these species adapt to the challenges of turning a terrestrial body into one that can survive at sea, and we investigate some of the most famous and confusing cases from the fossil record.

In the news: post-extinction oceans, croc eggs, damaged dino tails, and meat-eating dung beetles.

Time markers:

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The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org

Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0