Three Fossil Crinoids (Eretmocrinus & Aorocrinus) - Gilmore City, Iowa

These are three naturally associated fossil crinoids of the species Aorocrinus iola and Eretmocrinus tentor from the Gilmore City Formation of Gilmore City, Iowa. The two Eretmocrinus crinoids are clustered together near one edge of the specimen. The rock has been meticulously removed using air abrasives to reveal the beautifully preserved structures of these crinoids.

Aorocrinus iola (.5" long)
Eretmocrinus tentor (.5" & .5")

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