5.1" Colorful Asaphid Trilobite With Graptolites

About Graptolites

Graptolites are an extinct group of colonial, marine animals that thrived from the Cambrian through the Carboniferous period, reaching their peak diversity in the Ordovician. These ancient organisms are most commonly found as carbonized impressions on shale or slate, often appearing as fine, saw-blade or scribble-like markings on the rock surface.

Each graptolite colony, known as a rhabdosome, was composed of numerous tiny zooids housed in tubular structures called thecae. They are believed to have floated in the ocean, attached to planktonic structures or freely drifting with currents. Graptolite fossils are particularly important to geologists and paleontologists because they evolved rapidly and had a wide global distribution, making them excellent index fossils for dating Paleozoic rock layers. Notable graptolite-bearing formations include the Utica Shale in North America and the Welsh Black Shales in the UK.

About Trilobites

Trilobites are an extinct class of marine arthropods that thrived for nearly 270 million years, from the early Cambrian to the end of the Permian period (around 521 to 252 million years ago). They are one of the most successful and diverse groups in the history of life, with over 25,000 described species spanning a wide range of sizes, shapes, and ecological niches. Known for their distinctive, segmented exoskeletons, trilobites provide invaluable insights into the evolutionary history of arthropods and the dynamics of ancient marine ecosystems.