This Specimen has been sold.
3.3" Crotalocephalina Trilobite - Atchana, Morocco
This is a nice, 3.3" long, trilobite (Crotalocephalina gibbus) quarried from the Lhandar Formation near Atchana, Morocco. It is nicely inflated and has been carefully extracted from the surrounding limestone so that it looks like it is ready to crawl off of the rock. The hypostome (mouthplate) has been exposed underneath its head.
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.