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Dongusuchus
''Dongusuchus'' (meaning ''Donguz River crocodile'' in Greek, for the area where the type specimen was foundSennikov, A. G. (1988) Novyye rauizukhidy iz triasa yevropeyskoy chasti SSSR. ''Paleontol. Zhurn.'' 1990 (2): 124-128 Moscow.) is an extinct genus of archosaur. Fossils have been found from the Donguz Formation outcropping on the banks of the Donguz River in the Orenburg Oblast of Russia. They are associated with a fossil assemblage called the ''Eryosuchus'' Fauna, named after the capitosaurid '' Eryosuchus'', the most common organism found from the assemblage. The locality dates back to the Anisian and early Ladinian stages of the Middle Triassic.Gower, D. J. and Sennikov, A. G. (2000). Early archosaurs from Russia. In M. J. Benton, E. N. Kurochkin, M. A. Shishkin, D. M. Unwin (eds.), ''The Age of Dinosaurs in Russia and Mongolia''. Cambridge University Press, Cambridge. pp. 140-159 Sennikov (1988) and Gower and Sennikov (2000) suggested that ''Dongusuchus'' was a grac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Donguz Formation
The Donguz Formation, Donguz Svita, or Donguz Rocks (russian: Донгузские скалы) is a Middle Triassic geological formation that crops out on the right bank of Donguz River in Orenburg Oblast, Russia, across the settlement of Pervomaisky. The formation is equivalent to a biostratigraphic unit, the Donguz Gorizont. It is famous for its rich collection of the fossils of Middle Triassic tetrapods. It is a nature monument (особо охраняемых природных территорий (ООПТ)). Fossil content The following fossils have been found in the Donguz Formation: * Temnospondyls ** '' Eryosuchus antiquus'', Ochev ** '' E. garjainovi'', Ochev ** '' E. tverdochlebovi'', Ochev ** ''Bukobaja''? sp. ** '' Plagiorophus danilovi'' ** '' Plagioscutum ochevi'', Shishkin ** '' Plagiosternum paraboliceps'' (Konzhukova) * Thecodonts ** '' Jushatyria vjushkovi'' * Procolophonid ** '' Kapes serotinus'', Novikov * Proterosuchids ** '' Sarmatosuchus ochevi'', Sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytosaur
Phytosaurs (Φυτόσαυροι in greek) are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent groupings containing the same species, but some studies have identified non-phytosaurid phytosaurians. Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution. The name "phytosaur" means "plant reptile", as the first fossils of phytosaurs were mistakenly thought to belong to plant eaters. The name is misleading because the sharp teeth in phytosaur jaws clearly show that they were predators. For many years, phytosaurs were considered to be the most basal group of Pseudosuchia (crocodile-line archosaurs), meaning that they were thought to be more closely related to the crocodilians than to birds (the othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and Ma (million years ago). It is preceded by the Early Triassic Epoch and followed by the Late Triassic Epoch. The Middle Triassic is divided into the Anisian and Ladinian ages or stages. Formerly the middle series in the Triassic was also known as Muschelkalk. This name is now only used for a specific unit of rock strata with approximately Middle Triassic age, found in western Europe. Middle Triassic fauna Following the Permian–Triassic extinction event, the most devastating of all mass-extinctions, life recovered slowly. In the Middle Triassic, many groups of organisms reached higher diversity again, such as the marine reptiles (e.g. ichthyosaurs, sauropterygians, thallatosaurs), ray-finned fish and many invertebrate groups like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmoid Function
A sigmoid function is a mathematical function having a characteristic "S"-shaped curve or sigmoid curve. A common example of a sigmoid function is the logistic function shown in the first figure and defined by the formula: :S(x) = \frac = \frac=1-S(-x). Other standard sigmoid functions are given in the Examples section. In some fields, most notably in the context of artificial neural networks, the term "sigmoid function" is used as an alias for the logistic function. Special cases of the sigmoid function include the Gompertz curve (used in modeling systems that saturate at large values of x) and the ogee curve (used in the spillway of some dams). Sigmoid functions have domain of all real numbers, with return (response) value commonly monotonically increasing but could be decreasing. Sigmoid functions most often show a return value (y axis) in the range 0 to 1. Another commonly used range is from −1 to 1. A wide variety of sigmoid functions including the logistic and hype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Triassic Reptiles Of Europe
Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (other) * Middle Brook (other) * Middle Creek (other) * Middle Island (other) * Middle Lake (other) * Middle Mountain, California * Middle Peninsula, Chesapeake Bay, Virginia * Middle Range, a former name of the Xueshan Range on Taiwan Island * Middle River (other) * Middle Rocks, two rocks at the eastern opening of the Straits of Singapore * Middle Sound, a bay in North Carolina * Middle Township (other) * Middle East Music * "Middle" (song), 2015 * "The Middle" (Jimmy Eat World song), 2001 * "The Middle" (Zedd, Maren Morris and Grey song), 2018 *"Middle", a song by Rocket from the Crypt from their 1995 album ''Scream, Dracula, Scream!'' *"The Middle", a song by Demi Lovato from their debut album ''Don't Forget'' *"The Middle", a song by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisian Genera
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Epoch) and precedes the Ladinian Age. Stratigraphic definitions The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895. The name comes from ''Anisus'', the Latin name of the river Enns. The original type locality is at Großreifling in the Austrian state of Styria. The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of conodont species '' Chiosella timorensis'' in the stratigraphic record. Other stratigraphers prefer to use the base of magnetic chronozone MT1n. There is no accepted global reference profile for the base, but one ( GSSP or golden spike) was proposed at a flank of the mountain Deşli Caira in the Rom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Avemetatarsalians
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] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythrosuchus
''Erythrosuchus'' (from el, ἐρυθρός , 'red' and el, σοῦχος , 'crocodile') is an extinct genus of archosauriform reptile from the Triassic of South Africa. Remains have been found from the Cynognathus Assemblage Zone of the Beaufort Group in the Karoo of South Africa. In the Late Triassic, the ecological niche left by ''Erythrosuchus'' was filled by archosaurs like ''Saurosuchus'' and ''Postosuchus''. Description ''Erythrosuchus'' was the largest predator of its time, and was around long. It walked on all fours and had limbs which were positioned semi-vertically under its body, unlike the more sprawling gait of most earlier reptiles. Its head was large and theropod-like, reaching a length of , and had sharp, conical teeth. ''Erythrosuchus'' was the largest erythrosuchid, but apart from its size, was largely similar in appearance to other related genera. It had a large head and comparatively short neck. One of the few distinguishing features of ''Erythrosuchus' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudosuchia
Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Prior to 2011, the clade Pseudosuchia was often called Crurotarsi in reference to the crurotarsal ankle found in almost all members of the group, which traditionally included phytosaurs, ornithosuchids, and suchians. However, a major 2011 study of Triassic archosaur relations proposed that phytosaurs were not closely related to other traditional "crurotarsans", at least compared to "bird-line archosaurs" (Avemetatarsalians) such as pterosaurs and dinosaurs. As a result, the possession of a crurotarsal ankle was considered a plesiomorphic ("primitive") feature retained by pseudosuchians. Crurotarsi now refers to a broader group of reptiles including Pseudosuchia, Phytosauria, and Avemetatarsalia. Despite Pseudosuchia meaning "false crocodiles", th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euparkeria
''Euparkeria'' (; meaning "Parker's good animal", named in honor of W.K. Parker) is an extinct genus of archosauriform from the Middle Triassic of South Africa. It was a small reptile that lived between 245-230 million years ago, and was close to the ancestry of Archosauria, the group that includes dinosaurs, pterosaurs, birds and crocodilians. ''Euparkeria'' had hind limbs that were slightly longer than its forelimbs, which has been taken as evidence that it may have been able to rear up on its hind legs as a facultative biped. Although ''Euparkeria'' is close to the ancestry of fully bipedal archosaurs such as early dinosaurs, it probably developed bipedalism independently. ''Euparkeria'' was not as well adapted to bipedal locomotion as dinosaurs and its normal movement was probably more analogous to a crocodilian high walk. Palaeobiology Locomotion The hind limbs of ''Euparkeria'' are somewhat longer than its forelimbs, which has led many researchers to conclude that it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paratype
In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Often there is more than one paratype. Paratypes are usually held in museum research collections. The exact meaning of the term ''paratype'' when it is used in zoology is not the same as the meaning when it is used in botany. In both cases however, this term is used in conjunction with ''holotype''. Zoology In zoological nomenclature, a paratype is officially defined as "Each specimen of a type series other than the holotype.", ''International Code of Zoological Nomenclature'' In turn, this definition relies on the definition of a "type series". A type series is the material (specimens of organisms) that was cited in the original publication of the new species or subspecies, and was not excluded from being type material by the author (th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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