Ancient Trilobite Fossils

Trilobite meaning "three lobes" are and extinct arthropod that form the species Trilobita. Trilobites are comprised of one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period(approximately 251 million years ago) and they flourished throughout the lower Paleozoic before slipping towards extinction, when, during the Devonian, all trilobite orders except the Proetida died out. The last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.