Platyscutellum formosum formosum, Devonian trilobite fossil. Trilobites were arthropods that fed as they crawled on the seabed. They lived between 500 and 300 million years ago and are now extinct. This specimen dates from the Middle Devonian, and was found in rocks at El Atchama, Laatchana, Morocco. This is a complete individual, with a very wide, short cephalon, a glabella that widens forwards and large holochroal eyes. The pleurae terminate in long extended spines. There is a large pygidium with ribs. This specimen is 5.5 centimetres long.