1.45" Megistaspis Trilobite With Pos/Neg - Fezouata Formation
This is a 1.45" long Megistaspis (Ekeraspis) trilobite from the Fezouata Formation of Morocco. It includes both the positive and negative split of the fossil.
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.