Glyphaspis capella, a middle Cambrian ptychopariid trilobite from the Conasauga Formation, approximately 1.6 inches (4.2 centimeters) long. Ptychopariids were among the most common trilobites in the Cambrian and also the longest-surviving group through the Paleozoic Era.
Cambrian Ptychopariid Trilobite
Photo courtesy of David R. Schwimmer Ⓒ 2017