This Specimen has been sold.
2.6" Asaphus Raniceps Trilobite - Russia
This is a nice example of one of less often seen species of Russian asaphid trilobites, Asaphus raniceps. It comes from the Lower Ordovician, Kunda Horizen near the Volkhov River. It would be 2.6" long if outstretched. Shell restoration appears to be less than 5%, mostly on it's 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 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.