Trilobite - Pygidium

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Trilobites form a group of extinct marine arachnomorph arthropods that constitute the class Trilobita. As one of the earliest-known groups of arthropods, trilobites emerged early in Earth's history. Their first appearance in the fossil record marks the base of the Atdabanian stage of the Early Cambrian period, which dates back approximately 521 million years ago. Throughout the lower Paleozoic era, trilobites thrived until they began a gradual decline and eventually went extinct during the Devonian period. However, not all trilobite orders disappeared; some, including the Proetids, survived this mass extinction event. Trilobites left behind an extensive fossil record due to their diverse nature and easily fossilized exoskeletons. This has facilitated crucial contributions to various fields of study, such as biostratigraphy, palaeontology, evolutionary biology, and plate tectonics. The classification of trilobites places them within the arthropod subphylum Schizoramia, which is equivalent to the Arachnata superclass. Trilobites exhibited diverse lifestyles, including predation, scavenging, filter feeding, and swimming, with some species even forming symbiotic relationships with sulfur-eating bacteria from which they derived food. This diversity in lifestyles is similar to that of modern marine arthropods, although parasitism remains a topic of scientific debate. The scanning of fossils in Shropshire reveals insights into the lives of trilobites and sheds light on their evolution and extinction.