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Acipenser Albertensis
''Acipenser'' is a genus of sturgeons, containing three species native to freshwater and estuarine systems of eastern North America and Europe. It is the type genus of the family Acipenseridae and the order Acipenseriformes. Taxonomy Prior to 2025, ''Acipenser'' contained almost all species in the Acipenseridae outside of ''Huso'' and the "shovelnose" sturgeons (''Scaphirhynchus'' and '' Pseudoscaphirhynchus''). However, such a placement is now known to be paraphyletic with respect to the other genera, and these species have since been split into ''Huso'' and '' Sinosturio''. ''Acipenser'' in the strict sense (''sensu stricto'') has been redefined with only 3 species. This is an ancient genus, with phylogenetic evidence suggesting that it is the most basal sturgeon genus, having diverged from other sturgeons during the Early Cretaceous period. Several fossil species known as far back as the Late Cretaceous, with the fossils of two species ('' A. praeparatorum'' and '' A. amnisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Sturgeon
The Atlantic sturgeon (''Acipenser oxyrinchus'') is a large species of sturgeon native to both sides of the Atlantic Ocean, and associated river basins. It is a member of the family Acipenseridae, and, along with other sturgeon, it is sometimes considered a living fossil. The main range of the Atlantic sturgeon is in eastern North America, extending from New Brunswick, Canada, to the eastern coast of Florida, United States. A highly endangered Disjunct distribution, disjunct population occurs in the Baltic region of Europe (today only through a reintroduction project). The Atlantic sturgeon was in great abundance when the first European settlers came to North America, but has since declined due to overfishing, water pollution, and habitat impediments such as dams. It is considered threatened, endangered, and even locally extinct in many of its original habitats. The fish can reach 60 years of age, in length and over in weight. Taxonomy Alongside its relative the European se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a phylogenetic tree#Rooted tree, rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, Phylogenetic diversity, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and cladogenesis, diversification. However, such a correlation does not make a given ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological Type (biology), type wiktionary:en:specimen, specimen (or specimens). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the International Code of Nomenclature for algae, fungi, and plants, code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name with that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samuel L
Samuel L. may refer to: * Samuel L. Jackson (born 1948), American actor * Samuel L. Clemens aka Mark Twain (1835 – 1910), American author * Samuel L. Devine (1915 – 1997), American politician * Samuel L. Gravely Jr. (1922 – 2004) African-American naval officer * Samuel L. Greitzer (1905 – 1988), American mathematician * Samuel L. Lewis (1896 – 1971) American mystic and horticulturalist * Samuel L. Mitchill (1764–1831) American physician, naturalist, and politician * Samuel L. Popkin (born 1942), American political scientist * Samuel L. Southard (1787 – 1842), American statesman {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acipenser Oxyrinchus
The Atlantic sturgeon (''Acipenser oxyrinchus'') is a large species of sturgeon native to both sides of the Atlantic Ocean, and associated river basins. It is a member of the family Acipenseridae, and, along with other sturgeon, it is sometimes considered a living fossil. The main range of the Atlantic sturgeon is in eastern North America, extending from New Brunswick, Canada, to the eastern coast of Florida, United States. A highly endangered disjunct population occurs in the Baltic region of Europe (today only through a reintroduction project). The Atlantic sturgeon was in great abundance when the first European settlers came to North America, but has since declined due to overfishing, water pollution, and habitat impediments such as dams. It is considered threatened, endangered, and even locally extinct in many of its original habitats. The fish can reach 60 years of age, in length and over in weight. Taxonomy Alongside its relative the European sea sturgeon (''A. s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vadim Dimitrievitch Vladykov
Vadim (Cyrillic: Вадим) is a Slavic masculine given name derived from the Ruthenian word ''vaditi'' (), meaning ''to blame'' or as a diminutive of Vadimir. ''Dictionary of Russian Names''. : Vadym; : Vadzim. Notable people with the name include: Mononymic *[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acipenser Oxyrinchus Desotoi
The Gulf sturgeon (''Acipenser desotoi'') is a species of sturgeon Endemism, endemic to the southeastern United States. An anadromous fish, it inhabits the Gulf of Mexico and spawns in a number of rivers that drain into it, from southern Florida west to eastern Louisiana. It has one of the southernmost distributions of all sturgeon, which otherwise tend to inhabit cooler habitats in more northern latitudes. The Gulf sturgeon is listed as threatened under the United States Endangered Species Act, having been listed in 1991. Critical habitat, reflecting the range of the subspecies deemed essential for its continued survival, has been designated (see map). The historical range is thought to have been from the Suwannee River on the western coast of Florida to the Mississippi River, and marine waters of the central and eastern portions of the Gulf of Mexico. Three sturgeon species in genus ''Scaphirhynchus'' share river territory with the Gulf sturgeon; none of the other sturgeon spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acipenser Gigantissimus
''Acipenser'' is a genus of sturgeons, containing three species native to freshwater and estuarine systems of eastern North America and Europe. It is the type genus of the family Acipenseridae and the order Acipenseriformes. Taxonomy Prior to 2025, ''Acipenser'' contained almost all species in the Acipenseridae outside of ''Huso'' and the "shovelnose" sturgeons (''Scaphirhynchus'' and '' Pseudoscaphirhynchus''). However, such a placement is now known to be paraphyletic with respect to the other genera, and these species have since been split into ''Huso'' and '' Sinosturio''. ''Acipenser'' in the strict sense ('' sensu stricto'') has been redefined with only 3 species. This is an ancient genus, with phylogenetic evidence suggesting that it is the most basal sturgeon genus, having diverged from other sturgeons during the Early Cretaceous period. Several fossil species known as far back as the Late Cretaceous, with the fossils of two species ('' A. praeparatorum'' and '' A. am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous–Paleogene Extinction Event
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the extinction event, mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians. It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the current era, the Cenozoic. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the Cretaceous–Paleogene boundary, K–Pg boundary or K–T boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium, which is more common in asteroids than in the Earth's crust. As originally proposed in 1980 by a team of scientists le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicxulub Impact
The Chicxulub crater is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore, but the crater is named after the onshore community of Chicxulub Pueblo (not the larger coastal town of Chicxulub Puerto). It was formed slightly over 66 million years ago when an asteroid, about in diameter, struck Earth. The crater is estimated to be in diameter and in depth. It is believed to be the second largest impact structure on Earth, and the only one whose peak ring is intact and directly accessible for scientific research. The crater was discovered by Antonio Camargo and Glen Penfield, geophysicists who had been looking for petroleum in the Yucatán Peninsula during the late 1970s. Penfield was initially unable to obtain evidence that the geological feature was a crater and gave up his search. Later, through contact with Alan R. Hildebrand in 1990, Penfield obtained samples that suggested it was an impact feature. Evidence for the crater's imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanis (fossil Site)
Tanis is a private paleontological site in southwestern North Dakota, United States. It is part of the heavily studied Hell Creek Formation, a geological region renowned for many significant fossil discoveries from the Upper Cretaceous and lower Paleocene. Based solely on the Tanis team's publications, the Tanis is unique in that it allegedly records, in detail, concrete evidence of the direct effects of the giant Chicxulub impactor, Chicxulub asteroid impact which struck the Gulf of Mexico 66.043 million years ago, and wiped out all non-avian dinosaurs and many other species (the so-called Cretaceous–Paleogene extinction event, "K–Pg" or "K–T" extinction). The extinction event caused by this impact began the Cenozoic, in which mammals—including humans—eventually came to dominate life on Earth. Discoveries The site was originally discovered in 2008 by University of North Georgia Professor Steve Nicklas and field paleontologist Rob Sula. Their team successfully removed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acipenser Amnisinferos
''Acipenser'' is a genus of sturgeons, containing three species native to freshwater and estuarine systems of eastern North America and Europe. It is the type genus of the family Acipenseridae and the order Acipenseriformes. Taxonomy Prior to 2025, ''Acipenser'' contained almost all species in the Acipenseridae outside of ''Huso'' and the "shovelnose" sturgeons (''Scaphirhynchus'' and ''Pseudoscaphirhynchus''). However, such a placement is now known to be paraphyletic with respect to the other genera, and these species have since been split into ''Huso'' and ''Sinosturio''. ''Acipenser'' in the strict sense (''sensu stricto'') has been redefined with only 3 species. This is an ancient genus, with phylogenetic evidence suggesting that it is the most basal sturgeon genus, having diverged from other sturgeons during the Early Cretaceous period. Several fossil species known as far back as the Late Cretaceous, with the fossils of two species ('' A. praeparatorum'' and '' A. amnisinf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
