This Specimen has been sold.
3.6" Spectacular Paraceraurus Trilobite - Russia
This is an elegant, 3.6" long Paraceraurus macrophthalmus from the St. Petersburg Region of Russia. This long-spined Cheirurid has been nicely prepared from it's limestone tomb with both of the long genal spines free standing. The specimen appears to have been found ventrally and was flipped and remounted on the rock. There is some restoration to the tips of the spines.
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.