Trilobites are extinct marine arthropods. They first appear in the fossil record of the Early Cambrian period (521 million years ago); the last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.

This very dramatic specimen, here in C’s office, has expansive genal (cheek) and pygidial (tail) spines. It was found in the nearly half billion year old Middle Ordovician Asery Level deposits of the Volkhov River region near Saint Petersburg, Russia.