Trilobites (meaning “three lobes”) are a group of extinct marine arthropods that lived in the Palaeozoic Era. They first appeared during the Atdabanian stage of the Early Cambrian period (521 million years ago) and throughout the lower Palaeozoic. Their numbers began to slowly decline during the Silurian period until all trilobite orders, except the Proetids, died out during the Devonian period. Trilobites were widely dispersed throughout the world’s oceans and had many different lifestyles; some were predators and scavengers while others were filter feeders and lived off plankton. Currently there are approximately 17,000 species known, with many more still waiting to be discovered. Unfortunately, trilobites did not survive the Permian-Triassic extinction, where 95% of all life on Earth went extinct.