Protolenus, Cambrian 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 Lower Cambrian, and was found in the Jbel Wawrmast Formation, Oued Glenh, Morocco. It is a complete individual, with a semicircular cephalon with a wide glabella and deep occipital furrows. The eyes are at the end of the eye bar. It has small librigenes with spines. The pleurae terminate in small spines and the pygidium is tiny. This specimen is 4 centimetres long.