Fossil Echinoderms: A Closer Look at Their Feeding Habits

Echinoderms are a group of sea creatures known for their unique bodies and rich fossil history. One of their standout features is Mutable Collagenous Tissue (MCT), a special kind of connective tissue that can change shape quickly. This makes it hard to trace their evolution in the geological record. We found evidence of MCT in an ancient type of echinoderm called Blastoidea. Blastoidea had thin, hair-like structures called brachioles that helped them filter food from the water.Some old Blastoidea fossils from Germany show these brachioles as long, stiff structures forming a feeding fan, with MCT in a hard state. In other fossils, the brachioles are in different positions, hinting at nervous control over each brachiole's MCT. Some fossils even show the brachioles changing from stiff to flexible states, as if they were quickly buried.