This Specimen has been sold.
Two Nice Paciphacops Trilobites (One Enrolled & One Prone)
This is a pair of naturally associated Paciphacops cambelli trilobites from the Haragan Formation in Oklahoma. One specimen is fully enrolled and other is mostly outstretched with just its tail tucked.. Both would be around 1" long if outstretched. They were nicely prepared using air abrasives under microscope and display well on the creme colored limestone.
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.