Trilobites are a well-known fossil group of extinct marine arthropods, one of the earliest known groups. They first appeared in the fossil record in the Early Cambrian Period (526 million years ago), flourishing throughout the lower Paleozoic Era before beginning a drawn-out decline to extinction when, during the Devonian Period, almost all trilobite orders died out before finally disappearing in the mass extinction at the end of the Permian Period, about 250 million years ago. Trilobites were among the most successful of all life forms, roaming the oceans for over 270 million years. Offered here is a lot of four complete fossilized trilobites, including Walliserops trifurcatus, Ceratarges armatus, Cyphaspis tafilalet and Leonaspis deflexa. These fossils date to the Devonian Period (419.2–358.9 million years ago) and were unearthed in Morocco. The Walliserops measures 2-3/8" long and is nicely preserved, w/the most striking feature of the morphology of Walliserops - three-pronged "trident" rostrum that rises from the glabella - present. Ceratarges measures 1.5" long and is nicely preserved, w/the most striking feature of the morphology of Ceratarges - several elaborate spines - present. Cyphaspis measures 1-3/8" long and is nicely preserved, w/two antenna-like stalks rising from the glabella and three trailing spines. Leonaspis measures 1-3/8" long and is nicely preserved, though its cephalon, or head section is slightly disjointed on one side. Nice grouping of trilobites in wonderful condition. From the Robert M. Overstreet Collection and comes with COA.