Achistrum sp. Holothurian (Sea Cucumber) - Mazon Creek Fossil

Achistrum sp. – This holothurian is a member of the Echinoderms (body radially divided into five sections) and has a worm-like, soft, and leathery body. During preservation, its cylindrical form dries out, leaving desiccation cracks. A ring of approximately 15 small calcareous plates form the mouth that supports the esophagus and small fish-hook shaped sclerites are embedded throughout the body. Holothurians are not uncommon in the Essex Fauna, but are extremely rare in the overall fossil record.