Trilobite

Trilobites are remarkable, hard-shelled, segmented creatures that existed 520 million years ago in the Earth’s ancient seas. They went extinct before dinosaurs even came to existence, and are one of the key signature creatures of the Paleozoic Era, the first era to exhibit a proliferation of the complex life-forms that established the foundation of life as it is today. Although dinosaurs are the most well-known fossil animals, trilobites are also a favorite among those familiar with paleontology( the study of the development of life on Earth), and are found in the rocks of all continents. 

Please note that all trilobites are going to be slightly different then the one that is shown in the images.