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Eobelemnites
''Eobelemnites'' is a genus of belemnite from the Mississippian Epoch. See also * List of belemnites This list of belemnite genera is an attempt to create a comprehensive listing of all genera that have ever been included in the extinct subclass Belemnoidea, excluding purely vernacular terms. The list includes all commonly accepted genera, as we ... References Belemnites Carboniferous cephalopods {{paleo-cephalopod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belemnite
Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard. The calcitic guard is the most common belemnite remain. Belemnites, in life, are thought to have had 10 hooked arms and a pair of fins on the guard. The chitinous hooks were usually no bigger than , though a belemnite could have had between 100 and 800 hooks in total, using them to stab and hold onto prey. Belemnites were an important food source for many Mesozoic marine creatures, both the adults and the planktonic juveniles, and likely played an important role in restructuring marine ecosystems after the Triassic–Jurassic extinction event. They may have laid between 100 and 1,000 eggs. Some species may have been adapted to speed and swam in the tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Belemnites
This list of belemnite genera is an attempt to create a comprehensive listing of all genera that have ever been included in the extinct subclass Belemnoidea, excluding purely vernacular terms. The list includes all commonly accepted genera, as well as genera that are now considered invalid, doubtful (''nomina dubia''), or were not formally published (''nomina nuda''), as well as junior synonyms of more established names, and genera that are no longer considered belemites. Naming conventions and terminology follow the International Code of Zoological Nomenclature as indicated. The list currently contains 100 generic names. List of belemnites See also * Belemnoidea * List of ammonites * List of nautiloids This list of nautiloids is a comprehensive listing of all genera that have ever been included in the subclass Nautiloidea, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered in ... References :''Unc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpukhovian
The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from Ma to Ma. It is preceded by the Visean and is followed by the Bashkirian. The Serpukhovian correlates with the lower part of the Namurian Stage of European stratigraphy and the middle and upper parts of the Chesterian Stage of North American stratigraphy. Name and definition The Serpukhovian Stage was proposed in 1890 by Russian stratigrapher Sergei Nikitin and was introduced in the official stratigraphy of European Russia in 1974. It was named after the city of Serpukhov, near Moscow. The ICS later used the upper Russian subdivisions of the Carboniferous in its international geologic time scale. The base of the Serpukhovian is informally defined by the first appearance of the conodont '' Lochriea ziegleri'', though the utility and systematic stability of this species is not yet certain. No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mississippian Age
The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly 358.9 to 323.2 million years ago. As with most other geochronologic units, the rock beds that define the Mississippian are well identified, but the exact start and end dates are uncertain by a few million years. The Mississippian is so named because rocks with this age are exposed in the Mississippi Valley. The Mississippian was a period of marine transgression in the Northern Hemisphere: the sea level was so high that only the Fennoscandian Shield and the Laurentian Shield were dry land. The cratons were surrounded by extensive delta systems and lagoons, and carbonate sedimentation on the surrounding continental platforms, covered by shallow seas. In North America, where the interval consists primarily of marine limestones, it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (geology)
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belemnites
Belemnites may refer to: *Belemnitida Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to ..., an extinct order of cephalopods commonly known as "belemnites" * ''Belemnites'' (genus), a belemnite genus from the Early Jurassic {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
