Urchin Spine Fossils

These vials contain sea urchin spines from the Jurassic Period. This makes them between 145 and 201 million years old.

Sea urchins, which comprise the taxonomic class Echinoidea, are some of the oldest organisms on Earth. They first evolved 450 million years ago.

These creatures are widely distributed around the world, but the subgroup these fossils belong to, Cidaridae, primarily live in the abyssal zone of the oceans. Some are even known to live in the frigid waters of Antarctica.

Cidaridae spines form in many different shapes and sizes, including thin needles, fans, bulbs, and more.

These urchins are the only group that do not have skin on their spines. Interestingly, their massive, skinless spines, not only prevent predators from reaching their body, they also provide an ideal surface for sponges, bryozoans, and other tiny sea creatures to make their home.

*Last image from the Bulletin of the Museum of Comparative Zoology at Harvard College, 1863.