Ampyx priscus, Ordovician trilobite fossils. Trilobites were arthropods that fed as they crawled on the seabed. They lived between 500 and 300 million years ago and are now extinct. These specimens date from the Early to Middle Ordovician, and was found in the Arenig Series, in the Upper Fezouata Formation, Ait Zolli, Draa Valley, Morocco. These are two complete individuals with all three cephalic spines attached. It has no eyes, so it was blind. The backward projecting spines can be straight or curved showing flexibility. The perfect preservation suggests rapid burial. These specimens are 7 centimetres long.