<p><strong>SF Fig. 7.7.</strong> This fossil of <em>Paraceraurus exsul</em> belongs to a group of extinct marine animals called trilobites. Trilobites share a common evolutionary ancestor with modern insects, spiders, and crustaceans. This fossil dates to approximately 470 million years ago, during the Paleozoic era.</p>

SF Fig. 7.7. This fossil of Paraceraurus exsul belongs to a group of extinct marine animals called trilobites. Trilobites share a common evolutionary ancestor with modern insects, spiders, and crustaceans. This fossil dates to approximately 470 million years ago, during the Paleozoic era.

Image courtesy of Daderot, Wikimedia Commons