''Arctinurus boltoni'' is a large (up to 30 cm)

lichid Lichida is an order of typically spiny trilobite that lived from the Furongian to the Devonian period. These trilobites usually have 8–13 thoracic segments. Their exoskeletons often have a grainy texture or have wart or spine-like tubercles. S ...

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

of the mid-

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

. This trilobite reached about eight inches in length, though the normal adult

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

was about four inches. It lived in moderately deep-water in semi-tropical regions. ''Arctinurus'' fossils have been found in Europe and North America. ''Arctinurus'' was first reported during the construction of the

Erie Canal The Erie Canal is a historic canal in upstate New York that runs east-west between the Hudson River and Lake Erie. Completed in 1825, the canal was the first navigable waterway connecting the Atlantic Ocean to the Great Lakes, vastly reducing t ...

through soft Silurian shales and mudstones in upstate New York. Before the late 1990s, complete ''Arctinurus'' fossils were very rare. The vast majority of complete specimens were commercially mined near Middleport

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

, USA, in a shallow quarry in the Rochester Formation, and the trilobite is now relatively common in museum, university and private collections. ''Arctinurus'' tended to have

epibiont An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath"). The interaction between the two organisms is called epibiosis. An ep ...

s attached to the carapace.

References

* * Lichida Silurian trilobites of Europe Fossils of the United States Silurian trilobites of North America Jeffersonville Limestone Paleozoic life of Ontario Paleozoic life of Manitoba Paleozoic life of Quebec {{lichida-stub