In this episode, Xavier Bonilla has a dialogue with Danna Staaf about the history of cephalopods. They discuss the taxonomy of cephalopods and some of their anatomical features. They talk about how scientists understand cephalopods from the fossil record. They discuss the genesis of cephalopods and their first common ancestor along with the three sub-categories: ammonoids, coleoids, and nautiloids. They explain the importance of ammonoids, their shell, and how it became internalized. They mention the distinct features of Coleoids and the fascinating mystery of the enduring nautilus. They end by discussing current-day cephalopods and where their future is headed. 
Danna Staaf holds a PhD in invertebrate biology from Stanford university and is an expert on cephalopods. She continues to do research on cephalopods and has had her writing published in the Journal of Experimental Biology and numerous textbooks. She is the author of, Monarchs of the Sea: The Extraordinary 500-Million-Year History of Cephalopods which can be purchased here. You can find her work at her website. Twitter: @dannastaaf