This Specimen has been sold.
Two, Large, Crotalocephalina Trilobites - Flying Preparation
This is one of those trilobite specimens that makes you say, "wow they really do look like little aliens". It's a pair of fantastically prepared Crotalocephalina gibbus trilobites from Atchana, Morocco. What makes this particular specimen so special is they have been prepared in a "flying" pose by removing most of the rock from underneath creating a natural sculpture. The larger prone specimen is 4" long which i pretty much maximum size for the species.
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.