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Ancistroceras
''Ancistroceras'' is one of the two ancestral lituitids from the late Early Ordovician (Arenigian). The other being '' Holmiceras''. The shell is weakly annulate, starts off with 1.5 to 2 contiguous or slightly separated whorls followed by a rapidly expanding orthocone with an apical angle of about 30 deg. Growth lines are sinuous, show a pronounced hyponomic sinus in the coiled juvenile portion at the apex but almost none at the mature aperture of the orthcone. ''Holmiceras'' is similar except that its whorls are more loosely coiled and it is known only from the Arenigian whereas ''Ancistroceras'' ranges through most of the Middle Ordovician. ''Ancistroceras'' may have given rise to '' Rhynchorthoceras'' by a loss of the juvenile coiled portion, replacing it with a short semi-tubular cyrtoconic section. ''Ancistroceras'' may also have given rise to ''Lituites ''Lituites'' is an extinct nautiloid genus from the Middle Ordovician and type for the Lituitidae (a tarphycerid fami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lituitidae
The Lituitidae are a family of evolved tarphycerids characterized by a long orthoconic section that follows a coiled juvenile portion at the apex, along with a generally tubular siphuncle, which like that of the barrandeocerids is composed of thin connecting rings. Taxonomic position Flower and Kummel (1950) included the Lituitidae in the Barranderocerida which are now included in the Tarphycerida as a number of derived families. Furnish and Glenister (1964)Furnish & Glenister, 1964, Nautiloidea -Tarphycerida. Treatise on Invertebrate Paleontology Part K removed the Lituitidae to the Tarphycerida on the basis of observed similarities in the structure of the siphuncle. Other taxonomies, e.g. Dzik (1981) include the Lituitidae in the Orthocerida partly on the basis of the subcentral siphuncle and thin connecting rings, on the misconception that ''Rhynchorthoceras'' is ancestral. Classification The Lituitidae comprise two basic groups, based on general form. One is represented b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holmiceras
''Holmiceras'' is one of two ancestral lituitids from the late Early Ordovician (Arenigian). The other being ''Ancistroceras''. ''Holmiceras'' begins with about 1.5 to 2 loosely coiled whorls followed by a rapidly expanding orthocone, much like ''Ancistroceras'' except for the apical whorls and that Holmiceras is known only from the late Early Ordovician whereas ''Ancestroceras'' extends through the middle of the period. ''Holmiceras'' may have given rise to ''Angelinoceras'' which begins with an expanding open spiral. See also *List of nautiloids ''References'' * Flower, R. H. 1950. A Classification of the Nautiloidia. Jour Paleontology, V.24, N.5, pp 604–616, Sept. * Furnish & Glenister, 1964. Nautiloidea -Tarphycerida. Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchorthoceras
''Rhynchorthoceras'' is a Middle Ordovician genus characterized by a rapidly expanded, weakly annulate orthocone, like the orthoconic section of ''Ancistroceras'', but with only a curved, cyrtoconic apex instead of juvenile whorls. ''Rhynchorthoceras'' is probably derived from ''Ancistroceras'' by a loss of the tarphycerid type apex, although it has been included with the orthocerid Sinoceratidae. References *Flower, R. H. 1950. A Classification of the Nautiloidia. Jour Paleontology, V.24, N.5, pp 604–616, Sept. *Furnish & Glenister, 1964. Nautiloidea -Tarphycerida. Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ... Part K, Mollusca 3 ...Nautiloidea {{Taxonbar, from=Q7321718 Nautiloids Paleozoic life of Newfoundland and Labrador ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. 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 C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early 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. 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 Per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lituites
''Lituites'' is an extinct nautiloid genus from the Middle Ordovician and type for the Lituitidae (a tarphycerid family) that in some more recent taxonomies has been classified with the orthocerids and listed under the order Lituitida. Fossils have been found in New York, Argentina, Norway, Sweden, Estonia, and China. ''Lituites'' produced a shell with a planospirally coiled juvenile portion at the apex, reflective of its tarphycerid ancestry, followed by a long, moderately expanding, generally straight, orthoconic adult section with a subdorsal siphuncle connecting the chambers. The adult body chamber may equal or exceed the length of the chambered part of the orthoconic section. The mature aperture has a pair of pronounced ventrolateral lappets and a similar but shorter pair of dorsolateral lappets. ''Lituites'' gives its name to the term "lituiticone" which refers to a shell that is coiled in the early growth stage and later becomes uncoiled. References *Flower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Cephalopod 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 Iro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Ordovician First Appearances
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Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early Branch, a stream in Missouri * Early County, Georgia Other uses * ''Early'' (Scritti Politti album), 2005 * ''Early'' (A Certain Ratio album), 2002 * Early (name) * Early effect, an effect in transistor physics * Early Records, a record label * the early part of the morning See also * Earley (other) Earley is a town in England. Earley may also refer to: * Earley (surname), a list of people with the surname Earley * Earley (given name), a variant of the given name Earlene * Earley Lake, a lake in Minnesota *Earley parser, an algorithm *Earley ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
