Missouri: Delocrinus missouriensis (state fossil)

Missouri has chosen a crinoid, Delocrinus missouriensis, as its state fossil. This type of stalked echinoderm, known as a "sea lily," was a common inhabitant of the shallow sea that encroached on Missouri during the Pennsylvanian Period, around 290 million years ago. Crinoids of various types flourished in the oceans during most of the Paleozoic Era, and a few still survive today as "living fossils."

Echinoderms as a group also include sea urchins and starfish. They have pentagonal (five-fold) symmetry and an external skeleton composed of many small calcium carbonate plates. These plates interlock in sea urchins and sand dollars, increasing the likelihood that a complete creature will fossilize. In crinoids, the small ossicles usually disarticulate when the animal dies, and complete fossils are rare, whereas the ossicles themselves are abundant and widely collected.

Pennsylvanian limestones chock full of crinoid ossicles are commonly exposed in Missouri, especially the Callaway and Burlington Formations which outcrop near Springfield and Kansas City. Because of this, a group of students at Pleasant Lea Jr. High in Lee's Summit proposed the crinoid as the state fossil, and the legislature passed Act 10.090 on June 16, 1989, officially honoring Delocrinus missouriensis.

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Missouri symbols

Missouri's State Fossil