Trilobites are very ancient, now extinct organisms that lived from the early Cambrian, over 500 million years ago, well into the Permian period, some 250 million years ago. They were hard shelled, bottom-dwelling sea organisms, well known on account of the aptness of their hard scales for preservation and many fossils are found all over the world.Acadoparadoxides is an extinct genus of the trilobites belonging to the family Paradoxididae. They were carnivores living on the sea bottom at varying depth. They became extinct after the Middle Cambrian period. This specimen is from S Morocco, overall length 20 cm