This Specimen has been sold.
Bargain, 2.1" Enrolled Isotelus Trilobite - Mt. Orab, Ohio
This is a bargain, enrolled Isotelus maximus from the famous trilobite beds at Mt. Orab Ohio. The head and tail are present but the thorax is gone, hence the bargain price.
Trilobites were a very diverse group of extinct marine arthropods. They first appeared in the fossil record in the Early Cambrian (521 million years ago) and went extinct during the Permian mass extinction (250 million years ago). They were one of the most successful of the early animals on our planet with over 25k currently described species, filling nearly every evolutionary niche. Due in large part to a hard exoskeleton (shell), they left an excellent fossil record.