Trilobites 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 Atdabanian stage of the Early Cambrian period and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.
Eurypterus is an extinct genus of eurypterid, a group of organisms commonly called "sea scorpions". The genus lived during the Silurian period, from around 432 to 418 million years ago. Eurypterus is by far the most well-studied and well-known eurypterid. Eurypterus fossil specimens probably represent more than 95% of all known eurypterid specimens.
Pterygotus is a genus of giant predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Pterygotus have been discovered in deposits ranging in age from Middle Silurian to Late Devonian, and have been referred to several different species. Fossils have been recovered from four continents; Australia, Europe, North America and South America, which indicates that Pterygotus might have had a nearly cosmopolitan (worldwide) distribution. The type species, P. anglicus, was described by Swiss naturalist Louis Agassiz in 1839, who gave it the name Pterygotus, meaning "winged one". Agassiz mistakenly believed the remains were of a giant fish; he would only realize the mistake five years later in 1844.
Calymene Brongniart, 1822, is a genus of trilobites in the order Phacopida, suborder Calymenina, that are found throughout North America, North Africa, and Europe in primarily Silurian outcrops. Calymene is closely related to Flexicalymene, and both genera are frequently found enrolled. Calymene trilobites are small, typically 2 cm in length. The cephalon is the widest part of the animal and the thorax usually has 13 segments.
Slimonia is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Slimonia have been discovered in deposits of Silurian age in South America and Europe. Classified as part of the family Slimonidae alongside the related Salteropterus, the genus contains three valid species, S. acuminata from Lesmahagow, Scotland, S. boliviana from Cochabamba, Bolivia and S. dubia from the Pentland Hills of Scotland and one dubious species, S. stylops, from Herefordshire, England. The generic name is derived from and honors Robert Slimon, a fossil collector and surgeon from Lesmahagow.
Dolichopterus is a genus of prehistoric sea scorpions, arthropods in the order Eurypterida. Fossils of Dolichopterus have been discovered in deposits ranging from Silurian to Devonian, and have been referred to several different species, some of them of dubious affinity to this genus.
Calymene blumenbachii Brongniart in Desmarest (1817), sometimes erroneously spelled blumenbachi, is a species of trilobite discovered in the limestone quarries of the Wren's Nest in Dudley, England. Nicknamed the Dudley Bug or Dudley Locust by 18th-century quarrymen it became a symbol of the town and featured on the Dudley County Borough Council coat-of-arms. Calymene blumenbachii is commonly found in Silurian rocks and is thought to have lived in the shallow waters of the Silurian, in low-energy reefs. This particular species of Calymene is unique to the Wenlock series in England, and comes from the Wenlock Limestone Formation in Much Wenlock and the Wren's Nest in Dudley. These sites seem to yield trilobites more readily than any other areas on the Wenlock Edge, and the rock here is dark grey as opposed to yellowish or whitish as it appears on other parts of the Edge, just a few miles away, in Church Stretton and elsewhere. This suggests local changes in the environment in which the rock was deposited.
Hughmilleria is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Hughmilleria have been discovered in deposits of the Silurian age in China and the United States. Classified as part of the basal family Hughmilleriidae, the genus contains three species, H. shawangunk from the eastern United States, H. socialis from Pittsford, New York, and H. wangi from Hunan, China. The genus is named in honor of the Scottish geologist Hugh Miller.
Rhinocarcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Rhinocarcinosoma have been discovered in deposits ranging of Late Silurian age in the United States, Canada and Vietnam. The genus contains three species, the American R. cicerops and R. vaningeni and the Vietnamese R. dosonensis. The generic name is derived from the related genus Carcinosoma, and the Greek ῥινός, referring to the unusual shovel-shaped protrusion on the front of the carapace of Rhinocarcinosoma, its most distinctive feature.
Carcinosomatidae is a family of eurypterids, an extinct group of aquatic arthropods. They were members of the superfamily Carcinosomatoidea, also named after Carcinosoma. Fossils of carcinosomatids have been found in North America, Europe and Asia, the family possibly having achieved a worldwide distribution, and range in age from the Late Ordovician to the Early Devonian. They were among the most marine eurypterids, known almost entirely from marine environments.
Pterygotioidea is a superfamily of eurypterids, an extinct group of aquatic arthropods. Pterygotioids were the most derived members of the infraorder Diploperculata and the sister group of the adelophthalmoid eurypterids. The group includes the basal and small hughmilleriids, the larger and specialized slimonids and the famous pterygotids which were equipped with robust and powerful cheliceral claws.
Bumastus is an extinct genus of corynexochid trilobites which existed from the Early Ordovician period to the Late Silurian period. They were relatively large trilobites, reaching a length of 6 in (15 cm). They were distinctive for their highly globular, smooth-surfaced exoskeleton. They possessed well-developed, large compound eyes and were believed to have dwelled in shallow-water sediments in life.
Calymene celebra is a Silurian species of trilobites of the order Phacopida and also the state fossil of Wisconsin. It is found in Illinois, Indiana, and Wisconsin.
Paleontology in Illinois refers to paleontological research occurring within or conducted by people from the U.S. state of Illinois. Scientists have found that Illinois was covered by a sea during the Paleozoic Era. Over time this sea was inhabited by animals including brachiopods, clams, corals, crinoids, sea snails, sponges, and trilobites.
Paleontology in Wisconsin refers to paleontological research occurring within or conducted by people from the U.S. state of Wisconsin. The state has fossils from the Precambrian, much of the Paleozoic, some a parts of the Mesozoic and the later part of the Cenozoic. Most of the Paleozoic rocks are marine in origin. Because of the thick blanket of Pleistocene glacial sediment that covers the rock strata in most of the state, Wisconsin’s fossil record is relatively sparse. In spite of this, certain Wisconsin paleontological occurrences provide exceptional insights concerning the history and diversity of life on Earth.
Necrogammarus salweyi is the binomial name applied to an arthropod fossil discovered in Herefordshire, England. The fossil represents a fragmentary section of the underside and an appendage of a pterygotid eurypterid, a group of large and predatory aquatic arthropods that lived from the late Silurian to the late Devonian. The Necrogammarus fossil is Late Silurian in age and its generic name means "dead lobster", deriving from Ancient Greek νεκρός and Latin gammarus ("lobster").
Ciurcopterus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Ciurcopterus have been discovered in deposits of Late Silurian age in North America. Classified as part of the family Pterygotidae, the genus contains two species, C. sarlei from Pittsford, New York and C. ventricosus from Kokomo, Indiana. The genus is named in honor of Samuel J. Ciurca, Jr., who has contributed significantly to eurypterid research by discovering a large amount of eurypterid specimens, including the four specimens used to describe Ciurcopterus itself.
Coalbrookdale Formation, earlier known as Wenlock Shale or Wenlock Shale Formation and also referred to as Herefordshire Lagerstätte in palaeontology, is a fossil-rich deposit (Konservat-Lagerstätte) in Powys and Herefordshire at the England–Wales border in UK. It belongs to the Wenlock Series of the Silurian Period within the Homerian Age. It is known for its well-preserved fossils of various invertebrate animals many of which are in their three-dimensional structures. Some of the fossils are regarded as earliest evidences and evolutionary origin of some of the major groups of modern animals.
Homotrypa is an extinct genus of bryozoans from the Ordovician and Silurian periods, known from fossils found in the United States. Its colonies are branch-like and have small monticules made of groups of three or four larger zooecia slightly protruding out from the main surface of the colony. In cross section, the zooecia are erect in axis and gently curve toward the surface of the colony.
