The discovery of a 475-million-year-old trilobite exoskeleton in Tennessee is a glimpse into an ancient past.
An 11-year-old Tennessee girl recently made an extraordinary find and discovered a 475-million-year-old fossil of an empty exoskeleton from an ancient creature called trilobites, as we reported recently. And it reveals the amazing reality of how our planet looked long before humanity's existence, when creatures like the trilobite thrived in the seas.
The intact trilobite exoskeleton, an extremely rare find, as such exoskeletons typically split into many pieces, was found on the shores of Douglas Lake in East Tennessee by Ryleigh Taylor. This marine arthropod has long been extinct, but hundreds of millions of years ago it lived right here in the United States when it was covered in water.
The trilobite is an extraordinary creature that first appeared in the early Cambrian period 521
Trilobites are typically quite small, but not always. The largest ever found was Isotelus rex in Manitoba, which was 28 inches long and 16 inches wide.
Today, trilobite fossils can be found all over the world today, due to the enormous number of species that are found in Earth's history (although the discovery of an intact exoskeleton is rather rare).
Long before humans, these creatures populated the Earth and made them to a very different place than we know today. It is a frightening reminder of how little time we spent on this earth as a species and how different our planet looked before eons.
The following is an excerpt from Wikipedia about trilobites.
Trilobites are a fossil group of extinct marine arachnomorphic arthropods that make up the genus Trilobita. Trilobites are one of the earliest known groups of arthropods. The first occurrence of trilobites in the fossil record defines the basis of the early Cambrian atdaban phase (521 million years ago), and they flourished during the lower Paleozoic before deconvolutionally slow decay to extinction. All trilobite orders except the proetids are extinct , Trilobites disappeared in the mass extinction at the end of the Permian about 252 million years ago. The trilobites were among the most successful of all early animals that roamed the oceans for over 270 million years.
By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had a large variety and a slightly fossilized exoskeleton, they left an extensive fossil record, with about 17,000 known species that extend over the Paleozoic. The study of these fossils has made important contributions to biostratigraphy, paleontology, evolutionary biology and plate tectonics. Trilobites are often placed within the arthropod subphylum Schizoramia within the superclass Arachnomorpha (equivalent to the Arachnata), although several alternative taxonomies are found in the literature.
Trilobites had many lifestyles; Some moved over the seabed as predators, scavengers, or filter eaters, and some swam and planked plankton. Most lifestyles that are expected of modern marine arthropods are seen in trilobites, with the possible exception of parasitism (where scientific debate continues). Some trilobites (especially the Olenidae family) even seem to have developed a symbiotic relationship with sulfur-eating bacteria from which they derived food.
Trilobites seem to have been exclusively marine organisms, since the fossil remains of trilobites are always found in rocks with fossils of other saltwater animals such as brachiopods, crinoids and corals. Within the marine Paleo environment, trilobites have been found in a wide range from extremely shallow water to very deep water. Trilobites, such as brachiopods, crinoids and corals, are found on every modern continent, occupying every ancient ocean from which Paleozoic fossils were extracted.  The remains of trilobites can range from the conserved body to pieces of the outer skeleton hidden in the process of ecdysis. In addition, the traces of trilobites living on the seabed are often preserved as trace fossils.
There are three major forms of trace fossils associated with trilobites: Rusophycus; Cruziana & Dipichnites – such trace fossils represent the conserved life activity of trilobites active on the seafloor. Rusophycus, the resting lane, are trilobite excavations with little or no forward movement and ethological interpretations suggest peace, shelter and hunting. Cruziana, the feeding track, are furrows through the sediment, which are believed to represent the movement of trilobites during deposit feeding. It is believed that many of the fossil fossils are traces of trilobites migrating on the sedimentary surface. However, care must be taken to record similar trace fossils in freshwater and post-Paleozoic deposits of non-trilobite origin.
Trilobite fossils are found worldwide, with many thousands of known species. Because they appeared rapidly in geological time and mowed like other arthropods, trilobites serve as excellent index fossils, allowing geologists to determine the age of the rocks in which they are located. They were among the first fossils that attracted wide attention, and each year new species are discovered.
In the United States, the most publicly available collection of trilobites is in Hamburg, New York. Informally known as Penn Dixie, it was discovered by Dan Cooper in the 1970s. The slate quarry stopped mining in the 1960s, but the amount of rock quarrying had large trilobite occurrences. As a well-known rock collector he has aroused the scientific and public interest in this place. The fossils were dated 350 million years ago, when the western New York region was 30 degrees south of the equator and was completely covered in water. The site was acquired by Vincent Bonerb, Cavalcoli, from the City of Hamburg in cooperation with the Hamburg Natural History Society to protect the land from development. In 1994, the quarry became the Penn Dixie Fossil Park & Nature Reserve when it received status 501 (c) 3 and was opened for inspection and collection of trilobite samples. The two most common samples are Phacops rana and Greenops.
A well-known site for trilobite fossils in the UK is Wren's Nest, Dudley in the West Midlands, where Calymene blumebachii occurs in the group of Silur Wenlock. Pictured on the coat of arms, this trilobite was named Dudley Bug or Dudley Locust by stone-cutters who once carved the abandoned limestone quarries. Llandrindod Wells, Powys, Wales, is another famous trilobite location. The well-known Elrathia kingi trilobite is abundant in the American era of Wheeler Shale in Utah.
Spectacularly preserved trilobite fossils, often showing soft body parts (legs, gills, antennae, etc.), were found in British Columbia. Canada (Cambrian Burgess Shale and similar places); New York, USA (Ordovician Walcott-Rust Quarry, near Russia and Beechers Trilobit bed, near Rome); China (Lower Cambrian Maotianshan Shales near Chengjiang); Germany (Devonian Hunsrück Slates near Bundenbach) and, much less often, in trilobite-bearing strata in Utah (Wheeler shale and other formations), Ontario and Manuels River, Newfoundland and Labrador
The French paleontologist Joachim Barrande (1799 (1883 ) performed his groundbreaking study of the trilobites in the Cambrian, Ordovician and Silurian of Bohemia and published the first volume of Système silurien du center de la Bohême in 1852.