17.5" Giant Asaphid Trilobite (Basilicus) - Fezouata Formation

Giant Asaphid Trilobite (Basilicus) - Fezouata Formation #277213

This is an absolutely massive 17.5" long Asaphid (Basilicus sp) trilobite fossil from the Fezouata Formation of Morocco. These giant Asaphids are quite rare to find complete now; they are found in limestone lenses within the massive shale unit of the formation. These limestone lenses are only exposed through erosion, a rather slow process in the desert. Over the decades, the sites have been scoured by diggers who have broken down all of the exposed lenses.

This one is near maximum size and is well preserved. It has about 15% restoration in total including the shell on the glabella and a section on the right edge of the tail.

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: over 25,000 species have been described, filling nearly every evolutionary niche. Due in large part to their hard exoskeletons (shells), they left an excellent fossil record.

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