Trilobites (pronounced traɪləˌbaɪt, meaning “three lobes”) are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Devonian, all trilobite orders, with the sole exception of Proetida, died out. Trilobites finally disappeared in the mass extinction at the end of the Permian about .
Anything and everything for your Dinosaur/Paleontology needs.most of my information comes from The Complete Guide to Dinosaurs and Prehistoric Reptiles by Chirs Mcnab
