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Apsidoceratidae
The Apsidoceratidae is a family of Middle and Upper Ordovician Barrandeocerina, (a suborder of tarphycerids), characterized by curved or coiled, smooth, transversely marked, or laterally costate shells, with a conspicuous hyponomic sinus. Early whorl sections tend to be subtriangular; become broader and dorsally impressed in closely coiled forms. Sutures are with lateral lobes in primitive forms but are without lateral lobes, but with ventral lobes in more advanced species with broader sections. Siphuncles are between the center and ventral margin, but not close to either. Genera remaining in the Apsidoceratidae include: :'' Apsidoceras'' :'' Charactoceras'' :'' Charactocerina'' :'' Deckeroceras'' :'' Fremontoceras'' :'' Wilsonoceras'' '' Chidleyenoceras'', previously assigned, tentatively, to the Apsidoceratidae has been reassigned (Flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plectoceratidae
The Plectoceratidae is a family of tarphycerids in the suborder Barrandeocerina established as a place for the genus '' Plectoceras''; defined (Sweet 1964) simply as coiled, costate barrandeocerids with subcentral adult siphuncle. According to Sweet, in the original ''Treatise'' Part K, the Plectoceratidae included only ''Plectoceras''. Flower, 1984, however added six other genera, two new and four removed from both the Barrandeoceratidae and Apsidoceratidae. Genera according to Flower, 1984 are: '' Plectoceras'' Hyatt -type genus '' Avilionella'' -removed from Barradeoceratidae '' Bodeiceras'', Flower 1984. added '' Chidleyenoceras'' - removed from the Apsidoceratidae '' Metaplectoceras'', Flower (?synonym for Plectoceras) '' Laureloceras'' Flower 1957, removed from Barrandeoceratidae '' Laurelplecoceras'' Flower 1984 -added According to Flower, 1984, ''Plectoceras'', and therefore the Plectoceratidae, is derived from the Tarphyceratid genus '' Campbelloceras'' while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarphycerida
The Tarphycerida were the first of the coiled cephalopods, found in marine sediments from the Lower Ordovician (middle and upper Canad) to the Middle Devonian. Some, such as '' Aphetoceras'' and '' Estonioceras'', are loosely coiled and gyroconic; others, such as '' Campbelloceras'', '' Tarphyceras'', and '' Trocholites'', are tightly coiled, but evolute with all whorls showing. The body chamber of tarphycerids is typically long and tubular,Furnish and Glenister 1964; Nautiloidea - Tarphycerida; In the ''Treatise on Invertebrate Paleontology'' Vol K; Teichert and Moore, (eds) GSA and U of Kansas Press 1964 as much as half the length of the containing whorl in most, greater than in the Silurian Ophidioceratidae. The Tarphycerida evolved from the elongated, compressed, exogastric Bassleroceratidae, probably ''Bassleroceras'', around the end of the Gasconadian through forms like ''Aphetoceras''. Close coiling developed rather quickly, and both gyroconic and evolute forms are fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barrandeocerina
The Barrandeocerina comprise a suborder of Early Paleozoic nautiloid cephalopods, primitively coiled but later forms may be cyrtoconic, gyroconic, torticonic, and even breviconic, all having empty siphuncles with thin connecting rings. The Barrandeocerina were originally defined as a separate order by Rousseau Flower (Flower and Kummel, 1950), but since then have been united within the Tarphycerida as a suborder (Teichert 1988). Derivation is from the Tarphyceratidae. In early forms the siphuncle is central or subcentral, orthochoanitic (septal necks short and straight), and thin, with tubular segments. Later forms include those with cyrtochoanitic septal necks (curved outward) and segments that may be slightly to strongly expanded into the chambers. Taxonomy Six families are included in the Barrandeocerina, (ex Barrandeocerida). : Barrandeoceratidae M Ord-M Dev :Plectoceratidae M-U Ord :Apsidoceratidae M-U Ord : Uranoceratidae U Ord-M Sil : Lechritrochoceratidae M-U Si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chidleyenoceras
''Chidleyenoceras'' is a Middle Ordovician tarphyceroid with a closely coiled, evolute shell; whorl section subquadrate, widest just above a broadly rounded venter; dorsum with a broad shallow impression; sutures moderately spaced, weakly sinuous; siphuncle large, subventral, apparently orthochoantitic with tubular segments. The tubular, subventral siphuncle separates ''Chidleyenoceras'' from the Apsidoceratidae (Sweet, 1964) where it had been included and puts it well into the Plectoceratidae (Flower, 1984). References * Flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ..., (1984). ''Bodeiceras''; a New Mohawkian Oxycone, with Revision of the Older Barrandeocerida and Discussion of the Status of the Order. Journal of Paleontology v. 58, no.6, pp 1372–1379, Nov. 1984. ... [...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] |
Prehistoric Nautiloid Families
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] |
Ordovician Molluscs
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. 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 flourish during the Ordovician as it did in the earlier Cambrian Perio ... [...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] |
