Episode 23: Meet the Echinoderms! Adventures with Ancient Sea Stars!

This episode was a blast to produce for a vertebrate scientist. I learned a ton about the echinoderms, the group of invertebrate animals to which sea stars, brittle stars, sea cucumbers, sea urchins, and crinoids belong. Be prepared for more adventures with invertebrate animals in the future.

Engineering Echinoderms with Elizabeth Clark!

Yale University Ph.D. student Elizabeth Clark, holding examples of modern-day echinoderms. The animal on the left is a sea star (Asteroidea), while the animal on the right is a brittle star (Ophiuroidea).

This episode would not have happened with Elizabeth Clark, graduate student in the Geology Department at Yale University and my gateway to echinoderms. As a part of the lab of Derek Briggs, Liz has studied a wide range of topics on echinoderm paleontology and biology. You can check out the original scientific paper on her Ordovician asteroid in Biology Letters and the Yale News story about the discovery. The original specimen of Protasterina flexuosa featured in the study is pictured below. It actually lived alongside the Flexicalymene trilobites featured in our previous invertebrate episode. You can see their fossils (and hundreds of thousands of others) at the Cincinnati Museum Center in Cincinnati, Ohio.

The ventral side of Protasterina flexuosa. From left to right: 1) a three-dimensional model of CT scan data, 2) the model with the water vascular system inside, 3) the water vascular system in 3D.

Scurrying with Sea Stars, Crawling with Crinoids, and Battling with Brittle Stars!

I had a lot of fun watching echinoderms locomote while making this podcast. I really cannot believe the diversity of movement styles they adopted throughout their history. A lot of this system is built on the water vascular system and associated tube feet, but many species explore different methods for motion. Check ‘em out below!

Sea star (Asteroidea) strande