3.2" Fossil Crinoid Plate - Missouri
This is a 3.2" plate of echinoderm fossils from The Burlington Formation, Ralls County, Missouri. This plate contains Physetocrinus ventricosus and Uperocrinus pyriformes. Other crinoid and shell fragments are also visible.
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.