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Cassinoceras
''Cassinoceras'' ("Cassin Horn") is a genus of nautiloids belonging to the endocerid family Piloceratidae that comes from the late Early Ordovician of eastern North America and adjacent territories.Teichert, Curt, 1964. Endoceratoidea ''in'' Treatise on Invertebrate Paleontology Part K Mollusca 3; Geological Soc. of America and Univ of Kansas Press; pp K171-K172, Piloceratidae. ''Cassinoceras'' is characterized by short, laterally compressed, rapidly expanding shells in which the upper, dorsal, surface has a convex curvature and diverges strongly from the essentially straight lower, ventral surface. The siphuncle which entirely fills the apical portion at the back of the shell is also compressed and vertically expanding, and is filled with simple endocones with a complex system of endosiphuncular blades through which a flattened endosiphuncular tube with widely spaced partitions runs. The shell of ''Cassinoceras'' grew to about 25 to 30 cm long.Moore, Raymond C., Lalicker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piloceratidae
The Piloceratidae are a compressed, rapidly expanding, cyrtoconic brevicones with holochoanitic ventral siphuncles and simple endocones. Most likely evolved from '' Clitendoceras'', a narrow, slightly endogastric genus intermediate in form between straight shelled ''Proendoceras'' and the bulkier Piloceratidae. Found in shallow carbonate marine sediments of Demingian through the Cassinian age, (essentially Arenigian, = early Middle -Upper Canadian) . Pilocerids split off from the Proterocameroceratidae very shortly after their inception and are the first family which the proterocamerocerids gave rise to. With the exception of Humeoceras, found in the middle Silurian, pilocerid genera are limited to the Lower Ordovician (Canadian in North America). The general shape of the pilocerid shell precludes an ambush predator lying in wait on the sea floor, or a stealthful hunter drifting through the water. Rather, they probably crawled over the sea floor, head down with the shell off th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautiloidea
Nautiloids are a group of cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and species rich, with over 2,500 recorded species. They flourished during the early Paleozoic era, when they constituted the main predatory animals. Early in their evolution, nautiloids developed an extraordinary diversity of shell shapes, including coiled morphologies and giant straight-shelled forms ( orthocones). No orthoconic and only a handful of coiled species, the nautiluses, survive to the present day. In a broad sense, "nautiloid" refers to a major cephalopod subclass or collection of subclasses (Nautiloidea ''sensu lato''). Nautiloids are typically considered one of three main groups of cephalopods, along with the extinct ammonoids (ammonites) and living coleoids (such as squid, octopus, and kin). While ammonoids and coleoids are monophyletic clades with exclusive ancestor-desce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocerida
Endocerida, from Ancient Greek ἔνδον (''éndon''), meaning "inside", and κέρας (''kéras''), meaning "horn", is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian. Their shells were variable in form. Some were straight ( orthoconic), others curved (cyrtoconic); some were long (longiconic), others short (breviconic). Some long-shelled forms like '' Endoceras'' attained shell lengths close to . The related '' Cameroceras'' is anecdotally reported to have reached lengths approaching , but these claims are problematic. The overwhelming majority of endocerids and nautiloids in general are much smaller, usually less than a meter long when fully grown. Morphology Endocerids had a relatively small body chamber as well as a proportionally large siphuncle, which in some genera reached nearly half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Ordovician
The Early Ordovician is the first epoch (geology), epoch of the Ordovician period, corresponding to the Lower Ordovician series (stratigraphy), series of the Ordovician system. It began after the Cambrian Stage 10, Age 10 of the Furongian epoch of the Cambrian and lasted from to million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages. History International Commission on Stratigraphy (ICS) appointed working groups on the boundaries of the Ordovician subdivisions in 1974. The boundaries were established by the fauna of conodonts and/or graptolites. In 1995, the Subcommission on Ordovician Stratigraphy, with the support of 90% majority of voting members, adopted the division of the Ordovician system into three series: Lower, Middle Ordovician, Middle and Upper Ordovician, Upper. In the same year, it was decided to divide each of the three series into two global stages. ''Tetragraptus approximatus'' zone was chosen as the base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authored work of currently 55 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post- Paleozoic era caenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, when needed, previously published vol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphuncle
The siphuncle is a strand of biological tissue, tissue passing longitudinally through the mollusc shell, shell of a cephalopod mollusc. 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 Septum (cephalopod), septa (walls) dividing the Camera (cephalopod), 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 Siphon (mollusc), 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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vermont
Vermont () is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, New Hampshire to the east, New York (state), New York to the west, and the Provinces and territories of Canada, Canadian province of Quebec to the north. According to the most recent U.S. Census estimates, the state has an estimated population of 648,493, making it the List of U.S. states and territories by population, second-least populated of all U.S. states. It is the nation's List of U.S. states and territories by area, sixth smallest state in area. The state's capital of Montpelier, Vermont, Montpelier is the least populous List of capitals in the United States, U.S. state capital. No other U.S. state has a List of largest cities of U.S. states and territories by population, most populous city with fewer residents than Burlington, Vermont, Burlington. Native Americans in the United States, Native Americans have inhabited the area for abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Epoch
{{Short description, Lower or Early Ordovician in North America The Canadian is the Lower or Early Ordovician in North America. The term is common in the older literature and has been well understood for more than a century. However it has no official recognition by the International Commission on Stratigraphy (ICS) and has been superseded by the more recently defined Ibexian series of western Utah. Background Dana introduced the Canadian as the name for a system separated from the rest of the Ordovician (Weller 1980), then known as the Lower Silurian, and referred to the rest of the Lower Silurian as the Trenton System. At that time the Ordovician had not yet been recognized. Later Ulrich redefined the Canadian as roughly equivalent to the Beekmantown strata of the Lower Ordovician. Flower (1957 p. 17) felt that recognition of the Canadian as a separate system would greatly solve problems in Early Paleozoic stratigraphy. As such, faunas in limestones of Canadian age are unifo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominion Of Newfoundland
Newfoundland was a British dominion in eastern North America, today the modern Canadian province of Newfoundland and Labrador. It included the island of Newfoundland, and Labrador on the continental mainland. Newfoundland was one of the original dominions under the Balfour Declaration of 1926, and accordingly enjoyed a constitutional status equivalent to the other dominions of the time. Its dominion status was confirmed by the Statute of Westminster, 1931, although the statute was not otherwise applicable to Newfoundland. In 1934, Newfoundland became the only dominion to give up its self-governing status, which ended 79 years of self-government. The abolition of self-government came about because of a crisis in Newfoundland's public finances in 1932. Newfoundland had accumulated a significant amount of debt by building a railway across the island, which was completed in the 1890s, and by raising its own regiment during the First World War. In November 1932, the governmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian language, Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norway in the Arctic Ocean. Constituting the westernmost bulk of the archipelago, it borders the Arctic Ocean, the Norwegian Sea and the Greenland Sea. Spitsbergen covers an area of , making it the largest island in Norway and the List of islands by area, 36th largest in the world. The administrative centre is Longyearbyen. Other settlements, in addition to research outposts, are the mining community of Barentsburg, the research community of Ny-Ålesund, and the mining outpost of Sveagruva. Spitsbergen was covered in of ice in 1999, which was approximately 58.5% of the island's total area. The island was first used as a whaling base in the 17th and 18th centuries, after which it was abandoned. Coal mining started at the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Nautiloid Genera
Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins 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 years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by the 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. It is based on an old conception of history that without written records there could be no history. The most common conception today is that history is based on evidence, however the concept of prehistory hasn't been completely discarded. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician Cephalopods
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Ma (million years ago) to the start of the Silurian Period Ma. The Ordovician, named after the 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 beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed 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 Geological Congress. Life continued to flour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
