Related Research Articles
The Cambrian Period was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period 485.4 mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian biology surpasses that of some later periods.
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 extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 20,000 species having been described.
Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are Fallotaspis, and Lemdadella, both belonging to this order. The first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. In terms of anatomical comparison, the earliest redlichiid species are probably ancestral to all other trilobite orders and share many primitive characters. The last redlichiid trilobites died out before the end of the Middle Cambrian.
Acimetopus Rasetti, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi (1943), Order Agnostida Salter (1864). It lived during the Botomian stage. = late Lower Cambrian Stage 4 ; the upper Botomian boundary corresponds to base of the Middle Cambrian, Miaolingian Series and Wuliuan stage.
Cobboldites Kobayashi, 1943, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida It lived during the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period.
Leptochilodiscus Rasetti, 1966 [= Kerberodiscus Bassett et al., 1976] is a genus of Lower Cambrian Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi (1943), Order Agnostida. It lived during the Botomian stage = late Lower Cambrian Stage 4 ; the upper Botomian Stage boundary corresponds to base of both the Middle Cambrian Wuliuan stage and Miaolingian Series.
Stigmadiscus Rasetti, 1966, is a genus of Lower Cambrian Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi (1943) Order Agnostida It lived during the Botomian stage, = late Lower Cambrian Stage 4 ; the upper Botomian Stage boundary corresponds to base of both the Middle Cambrian Wuliuan stage and Miaolingian Series.
Laudonia is an extinct genus of trilobites that lived during the early part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. There are currently two named species assigned to it.
Chelediscus Rushton, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida Salter (1864). The Treatise assigns this genus to the Calodiscidae; Cotton and Fortey (2005) however move it to the Weymouthiidae. Chelediscus lived during the later part of the Botomian stage.
Sinodiscus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the late Atdabanian stage, which lasted from 530 to 524 million years ago during the early part of the Cambrian Period.
Exigua is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from 501 to 497 million years ago during the Dresbachian faunal stage of the late Cambrian Period. Exigua is only known from the central part of the headshield or cranidium, so free cheeks, thorax and pygidium are unknown.
Crepicephalus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period.
The Dresbachian is a Maentwrogian regional stage of North America, lasting from 501 to 497 million years ago. It is part of the Upper Cambrian and is defined by four trilobite zones. It overlaps with the ICS-stages Guzhangian, Paibian and the lowest Jiangshanian.
Pagetia Walcott, 1916. is a small genus of trilobite, assigned to the Eodiscinid family Pagetiidae and which had global distribution during the Middle Cambrian. The genus contains 55 currently recognized species, each with limited spatial and temporal ranges.
Fritzolenellus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites, with three known species. It lived during the early part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. Fritzolenellus occurred in parts of the paleocontinent Laurentia in what are now Northwestern Canada, Northwestern Scotland, and North-Greenland.
The Terreneuvian is the lowermost and oldest series of the Cambrian geological system. Its base is defined by the first appearance datum of the trace fossil Treptichnus pedum around 538.8 million years ago. Its top is defined as the first appearance of trilobites in the stratigraphic record around 521 million years ago. This series' name was formally accepted by the International Commission on Stratigraphy in 2007.
Paleontology in Ohio refers to paleontological research occurring within or conducted by people from the U.S. state of Ohio. Ohio is well known for having a great quantity and diversity of fossils preserved in its rocks. The state's fossil record begins early in the Paleozoic era, during the Cambrian period. Ohio was generally covered by seawater from that time on through the rest of the early Paleozoic. Local invertebrates included brachiopods, cephalopods, coral, graptolites, and trilobites. Vertebrates included bony fishes and sharks. The first land plants in the state grew during the Devonian. During the Carboniferous, Ohio became a more terrestrial environment with an increased diversity of plants that formed expansive swampy deltas. Amphibians and reptiles began to inhabit the state at this time, and remained present into the ensuing Permian. A gap in the local rock record spans from this point until the start of the Pleistocene. During the Ice Age, Ohio was home to giant beavers, humans, mammoths, and mastodons. Paleo-Indians collected fossils that were later incorporated into their mounds. Ohio has been the birthplace of many world famous paleontologists, like Charles Schuchert. Many significant fossils curated by museums in Europe and the United States were found in Ohio. Major local fossil discoveries include the 1965 discovery of more than 50,000 Devonian fish fossils in Cuyahoga County. The Ordovician trilobite Isotelus maximus is the Ohio state invertebrate fossil.
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 Vermont comprises paleontological research occurring within or conducted by people from the U.S. state of Vermont. Fossils are generally uncommon in Vermont. Nevertheless, however, significant finds have been made in the state. Very few fossils are known in Vermont east of the Green Mountains due to the type of rock underlying that area. During the early part of the Paleozoic era, Vermont was covered by a warm, shallow sea that would end up being home to creatures like brachiopods, corals, crinoids, ostracoderms, and trilobites. There are no rocks in the state from the Carboniferous, Permian, Triassic, or Jurassic periods. The few Cretaceous rocks present contain no fossils. The Paleogene and Neogene periods are also absent from the local rock record. During the Ice Age, glaciers scoured the state. At times the state was inundated by seawater, allowing marine mammals to venture in. After the seawater drained away the state was home to mastodons. Local fossils had already attracted scientific attention by the mid-19th century when mastodon remains were found in Rutland County. In 1950 a major Paleozoic invertebrate find occurred. The Pleistocene Beluga whale Delphinapterus leucas is the Vermont state fossil.
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, 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.
References
- 1 2 Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Trilobita entry)". Bulletins of American Paleontology. 364: 560. Retrieved 2008-01-12.
- ↑ Kobayashi, T., 1944b: On the Cambrian formations in Yunnan and Haut-Tonkin and the trilobites contained. Miscellaneous notes on the Cambro-Ordovician geology and palaeontology 16. Japanese Journal of Geology and Geography, vol. 19, nos. 1–4, pp. 107–138, pls. 9–10.
 | This Redlichiida-related article is a stub. You can help Wikipedia by expanding it. |