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: Intro & Announcements: News: Main discussion, Part 1: Main discussion, Part 2: Patron question: Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcastGot a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/Lots more ways to connect with us: https://linktr.ee/common_descentThe Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.orgMusical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0