Serrodiscus

Serrodiscus is an extinct genus of trilobites that lived during the Early Cambrian period, roughly 540 to 509 million years ago. Fossils of Serrodiscus have been found in North America and Europe, including sites in Newfoundland, Greenland, and other Cambrian deposits. It represents one of the early groups of trilobites to appear in the fossil record.

Serrodiscus was a small trilobite, typically measuring only a few centimeters in length. Like many early Cambrian trilobites, it had a relatively simple body plan compared to later, more elaborate species. Its small dorsal exoskeleton is identified through features including its segmented thorax and distinctive cephalon.

Serrodiscus fossils have been recovered from Early Cambrian deposits in both North America and Europe. Notable finds include specimens from the Burgess Shale-type deposits in Newfoundland, Canada, and from Cambrian strata in Greenland. The genus has also been reported from other Cambrian sites in the North Atlantic region.

Serrodiscus belongs to an early group of trilobites within the order Agnostida or a closely related basal trilobite lineage, depending on the classification system used. It is recognized by features of its segmented dorsal exoskeleton, including the structure of its cephalon and pygidium. The taxonomy of early Cambrian trilobites has been revised multiple times as new fossil material is described.