Trilobite Fossil Replica, Large at 4.5 inches long, Realistic Replica, Worldwide Shipping This realistic replica measures 4.5 inches long (11.43cm) x 2.5 inches (6.35cm) wide. This is an accurate reconstruction (not an original fossil). Our replicas are cast and molded in house and are very true to scale. The replica is molded of resin, a hard polymer material which consists of some plastic and other natural/synthetic materials. *PROUDLY MADE IN THE USA* 10 Facts About Trilobites (from ZME Science): They thrived for almost 300 million years, from the Lower Cambrian (521 million years ago) to the start of the Mesozoic (250 million years ago). That means their period was hundreds of millions of years earlier than the Jurassic, when dinosaurs ruled the Earth. Trilobites are extinct arthropods, and some of the earliest one at that. They are distant relatives of modern lobsters and spiders. They lived in marine waters, although only some of them could actually swim. Many burrowed or crawled around on muddy sea floors. They were the first creatures to develop complex eyes. Their fossilized remains have been found on every continent on Earth, indicating that they thrived in all regions of the planet and all climates. This is why they’re some of the most common fossils. Like many modern arthropods, they were covered with a segmented exoskeleton. They could almost certainly roll up into a ball when threatened and some exoskeletons were covered in spines and bumps for added protection (or perhaps reproductive purposes). Also like many modern arthropods, they molted. This means they shed their exoskeleton as they grew. They greatly varied in size, from less than 1 cm to over 70 cm. They’re called ‘trilobites’ because their body could be split into three parts both longitudinally and axially. There are 10 “Orders” of trilobites featuring over 20,000 recognized species. THE ITEM(S) WILL BE SHIPPED OUT VIA STANDARD MAIL (USPS FIRST CLASS MAIL) (ESTIMATED SHIPPING TIME IS APPROXIMATELY 3-14 WORKING DAYS DEPENDING ON COUNTRY AND LOCATION). THANK YOU FOR LOOKING.