8" Cephalopod Fossil With Two Partial Crotalocephalina Trilobites
This is a really cool association featuring a 8" cephalopod fossil along with two partial Crotalocephalina gibbus trilobites from Atchana, Morocco. One of the partial trilobites has been prepared ventrally.
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.