This Specimen has been sold.
Aesthetic Crotalocephalina & Reedops Trilobite Association
This is a nice, naturally association of two different types of trilobites quarried at Atchana, Morocco. The larger trilobite is a Crotalocephalina gibbus that would be about 3.25" long and the smaller one is a nice, prone Reedops. Great shell preservation and preparation on both specimens.
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 described species, filling nearly every evolutionary niche. Due in large part to a hard exoskeleton (shell), they left a excellent fossil record.