The story of how the starfish got its arms reminds us that even animals that might be familiar to us today can have incredibly deep histories - ones that stretch back almost half a billion years.

Welcome back to Bizarre Beasts: Season Zero, where we are remastering episodes of Bizarre Beasts that were originally created for Vlogbrothers. This episode, Feather Stars! The ancient sea creature that has been on this planet for 500...

With some general information regarding echinoderms covered, it's time to get a sense of the diversity within this clade. First let's look at class Crinoidea, which contains the sea lilies and feather stars. These are fascinating...

With the hemichordates covered let's check out the echinoderms. Echinodermata is the other phylum in the clade Ambulacraria, and they are found all around the world. The most familiar organisms in this clade are starfish or sea stars,...