No.59 Trilobite

Trilobites were representative arthropods of the Paleozoic seas, inhabiting the ocean floor in a crawling manner. Their bodies were covered in a hard exoskeleton, and many species adopted a “ball-curling posture” to protect themselves by curling up like pill bugs. Over a period of approximately 300 million years, they evolved into a diverse array of over several thousand species, adapting to their environment.

The CT scans clearly captured not only the intricate layering of the exoskeleton but also the glimmer of pyrite scattered throughout the interior. This indicates that iron deposits crystallized within the soft tissues and crevices of the trilobite’s body during the fossilization process. Pyrite is a substance composed primarily of iron, and because it has a higher specific gravity than the surrounding materials, the use of CT scanning allowed us to visualize its distribution in three dimensions without destroying the fossil.