This Specimen has been sold.
3.45" Dicranurus Trilobite - Atchana, Morocco
This is bizarre trilobite looks like something you might see in an Alien's movie. It's fittingly name Dicranurus monstrosus. While fakes of this trilobite abound, real examples like this one are fairly rare. There is around 10% restoration on this specimen, hence the lower price. About half of the right genal spine has been restored, the back half of several of the tail spines as well as some restoration along the top of the axis on the lower half of the thorax.
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.