This is a wonderful example of the large, spiny, odontopleurid trilobite Selenopeltis buchi. It is 6" long including it's spines and unlike most examples you see it is not restored with just some crack repairs. These trilobites come from the Upper Tiouririne Formation and are quarried east of Erfoud, Morocco.
Comes with a display stand.
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.