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Adamsoceras
''Adamsoceras'' is a genus of actinocerids of the family Wutinoceratidae, with spheroidal siphuncle segments like '' Ormoceras'', but having a reticular canal system like ''Wutinoceras''. Adamsoceras has a slender, gently expanding, orthoconic shell that is slightly broader than high, i.e. depressed, with close spaced septa that form ventral lobes and a siphuncle that is near the ventral margin. ''Adamsoceras'' is known from rocks of Whiterockian age (early Middle Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...) in Nevada, the Baltic, Tasmania, and Manchuria. It may have been derived from ''Wutinoceras'', or from a common ancestor, and gave rise to ''Ormoceras''. The genotype is ''Adamsoceras isabelae'' from the upper Pogonip Group in Ikes Canyon in the Toquima Ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wutinoceratidae
The Wutinoceratidae are a family of early actinocerids defined by Shimazu and Obata in 1938Flower 1976. New American Wutinoceratidae with Review of Actinoceroid Occurrences in Eastern Hemisphere;PartI, Memoir 28; New Mexico Bureau of Mines and Mineral Resources for actinocerids with thick connecting rings and a complex irregular canal system. Actinocerids are generally straight shelled nautiloid cephalopods with a siphuncle composed of expanded segments, typically with thin connecting rings, in which the internal deposits are penetrated by a system of canals.Teichert 1964. Actinoceratoidea, Treatise on Invertebrate Paleontology, part K.(Nautiloidea) The Wutinoceratidae include three genera,Flower 1957. Studies of the Actinoceratida. Memoir 2; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM ''Wutinoceras'', ''Cyrtonybyoceras'', and ''Adamsoceras'', known especially from the early Middle Ordovician (Whiterock stage) in northeastern China and North America, but foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinocerida
The Actinocerida are an order of generally straight, medium to large cephalopods that lived during the early and middle Paleozoic, distinguished by a siphuncle composed of expanded segments that extend into the adjacent chambers, in which deposits formed within contain a system of radial canals and a narrow space along the inner side of the connecting ring known as a paraspatium. (Teichert 1964) Septal necks are generally short and cyrtochoanitic, some being recumbent, some hook shaped. Most grew to lengths of about but some, like the Huroniidae of the Silurian grew significantly larger. Ecology The Actinocerida inhabited shallow to quite deep waters, where they alternated between swimming and lying on the bottom. They were predatory, and able to control their buoyancy to a greater degree than their contemporaries. Derivation The derivation of the Actinocerida remains enigmatic. They first appear late in the Early Ordovician (Cassinian Stage, late Floian) with the Georginida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ormoceras
''Ormoceras'' is an actinocerid nautiloid genus and type for the family Ormoceratidae, found in North America from the late Chazyan through the early Cincinnatian of the Middle and Upper Ordovician, but which continued through the Devonian worldwide. ''Ormoceras'' is a characterized by its straight shell, more or less circular in cross section, and a relatively narrow subcentral siphuncle composed of globular segments in which the radial canals in the endosiphuncular canal system are straight and normal to the central canal. Septal necks are short, narrowly rounded or sharply recurved, but never recumbent. As with most actinocerids, cameral deposits are common. ''Ormoceras'' is derived from ''Adamsoceras'' which has a siphuncle with the same general form but in which the canal system is reticulate as in ''Wutinoceras''. ''Ormoceras'' gave rise to ''Deiroceras'' early on during the Mohawkian (Middle Ordovician) and slightly later to ''Troedssonoceras''. Ormoceras also gave ris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wutinoceras
''Wutinoceras'' is a genus of now extinct nautiloid cephalopods of the Wutinoceratidae family. It exhibits orthoconic actinocerids with ventral siphuncles composed of broadly expanded segments.Memoir 2, Studies of the Actinocerida, New Mexico Bureau of Mines and Mineral ResourcesMemoir 19, The First Great Expansion of the Actinoceroids, New Mexico Bureau of Mines and Mineral Resources Distinguishing characteristics ''Wutinoceras'', as with its family the Wutinoceratidae, has a reticulated canal system within the siphuncle, distinguishing it from later forms with arcuate canal systems. Septal necks, components of the siphuncle that project from the back side of the septa, are cyrtochoanitic (outwardly curved) and may be recumbent. Connecting rings are thick, reflective of the ancestral form. Varieties The three varieties of ''Wutinoceras'' are based on the form of the siphuncle, and each contains a number of species. These have not been ascribed to subgenera. They include th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Celtic Britons, Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Union of Geological Sciences, Intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rousseau H
Jean-Jacques Rousseau (, ; 28 June 1712 – 2 July 1778) was a Genevan philosopher, writer, and composer. His political philosophy influenced the progress of the Age of Enlightenment throughout Europe, as well as aspects of the French Revolution and the development of modern political, economic, and educational thought. His ''Discourse on Inequality'' and ''The Social Contract'' are cornerstones in modern political and social thought. Rousseau's sentimental novel ''Julie, or the New Heloise'' (1761) was important to the development of preromanticism and romanticism in fiction. His ''Emile, or On Education'' (1762) is an educational treatise on the place of the individual in society. Rousseau's autobiographical writings—the posthumously published '' Confessions'' (composed in 1769), which initiated the modern autobiography, and the unfinished '' Reveries of the Solitary Walker'' (composed 1776–1778)—exemplified the late 18th-century " Age of Sensibility", and featured an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ''Spirula''. In the case of the cuttlefish, the siphuncle is indistinct and connects all the small chambers of that animal's highly modified shell; in the other cephalopods it is thread-like and passes through small openings in the septa (walls) dividing the camerae (chambers). Some older studies have used the term siphon for the siphuncle, though this naming convention is uncommon in modern studies to prevent confusion with a mollusc organ of the same name. Function The siphuncle is used primarily in emptying water from new chambers as the shell grows. To perform this task, the cephalopod increases the saltiness of the blood in the siphuncle, and the water moves from the more dilute chamber into the blood through osmosis. At the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by ''Nautilus'' and ''Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, whereas in the Nautiloidea, the external shell remains. About 800 living species of cephalopods have been ident ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toquima Range
The Toquima Range is a mountain range, located primarily in Nye County with a small extension into Lander County, in Nevada, United States. Most of the range is included within the Humboldt-Toiyabe National Forest. The range reaches a maximum elevation of 11,949 feet (3,642 m) at the southern summit of Mount Jefferson. From Hickison Summit on U.S. Route 50, the range runs for approximately 71 miles (115 km) to the south-southwest. To its west are Big Smoky Valley, scenic State Route 376, and the large Toiyabe Range. To the east are remote Monitor Valley and the Monitor Range. Lying to the south of the range are U.S. Route 6 (Nevada) and the community of Tonopah, while to the north is U.S. Route 50 ("The Loneliest Highway in America"), leading to the small community of Austin. The high central section of the Toquima Range is a large area of subalpine tundra surrounding the three summits of Mount Jefferson. This section of the range is protected as the Alta T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Nautiloid Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Ordovician Animals Of North America
Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (other) * Middle Brook (other) * Middle Creek (other) * Middle Island (other) * Middle Lake (other) * Middle Mountain, California * Middle Peninsula, Chesapeake Bay, Virginia * Middle Range, a former name of the Xueshan Range on Taiwan Island * Middle River (other) * Middle Rocks, two rocks at the eastern opening of the Straits of Singapore * Middle Sound, a bay in North Carolina * Middle Township (other) * Middle East Music * "Middle" (song), 2015 * "The Middle" (Jimmy Eat World song), 2001 * "The Middle" (Zedd, Maren Morris and Grey song), 2018 *"Middle", a song by Rocket from the Crypt from their 1995 album '' Scream, Dracula, Scream!'' *"The Middle", a song by Demi Lovato from their debut album '' Don't Forget'' *"The Middle", a song ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By Rousseau H
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the intr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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