2.5" Macrocrinus Crinoid With Rare Split Anal Tube Pathology

This is a unique crinoid association plate collected from the Edwardsville Formation in Montgomery Co., Indiana. It contains a 2.5" Macrocrinus mundulus with a pathalogical anal tube which splits in two about two thirds the way up. There is also the crown of a 1.3" wide Agaricocrinus splendens present on this limestone. Really a unique specimen which is beautifully prepared by air-abrasives under microscope.

It is believed that crinoids from the Ramp Creek Limestone were buried in sediment from nearby deltas during storms. The resulting siltstone deposits are soft enough that fossils can be extracted in exquisite, three-dimensional relief.

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.

Macrocrinus mundulus & Agaricocrinus splendens
Montgomery Co., Indiana
Edwardsville Formation
4.4x3.1" matrix
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