Azygocrinus & Macrocrinus Crinoids - Missouri

This is a cool plate of Mississipian aged echinoderm fossils from Missouri. There are calyxes of two genus of crinoids (Azygocrinus rotundus & Macrocrinus verneuilianus) mounted on a slab of rock full of crinoid stem pieces from the same location.

Crinoids, sometimes commonly referred to as sea lilies, are animals, not plants. They are echinoderms related to starfish, sea urchins, and brittle stars. Many crinoid traits are like other members of their phylum; such traits include tube feet, radial symmetry, a water vascular system, and appendages in multiples of five (pentameral). They first appeared in the Ordovician (488 million years ago) and some species are still alive today.

About Crinoids