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Imperobator
''Imperobator'' ("powerful warrior") is a genus of paravian theropod that lived during the Maastrichtian stage of the Late Cretaceous period in what is now Antarctica. It contains a single species, ''I. antarcticus'', recovered from the Snow Hill Island Formation. Before its description, it was informally nicknamed the "Naze dromaeosaur", despite the lack of a "sickle claw" characteristic of the group. In 2019, the describing authors suggested that ''Imperobator'' was about the same size as ''Utahraptor''. Discovery and naming The only described species is known from a single specimen, UCMP 276000, which was first uncovered in 2003 at the early Maastrichtian-aged Cape Lamb Member of the Snow Hill Island Formation on James Ross Island, Antarctica. The Cape Lamb Member has been dated to the early Maastrichtian, about 71 million years ago. UCMP 276000 consists of an incomplete isolated left pes including a portion of the tibia, an incomplete astragalus, a partial calcaneus and fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow Hill Island Formation
The Snow Hill Island Formation is an Maastrichtian, Early Maastrichtian geologic Formation (geology), formation found on James Ross Island, James Ross Island group, Antarctica. Remains of a Paraves, paravian Theropoda, theropod ''Imperobator antarcticus''Ely & Case, 2019 have been recovered from it, as well as the elasmarian ornithopods ''Trinisaura santamartaensis'', ''List of informally named dinosaurs#Biscoveosaurus, Biscoveosaurus'' and ''Morrosaurus antarcticus'', the ankylosaurian ''Antarctopelta oliveroi'', and the shark ''Notidanodon'' sp. Alongside these described genera are also the remains of indeterminate Elasmosauridae, elasmosaurids,O'Gorman, 2012, p.2 lithostrotian titanosaurs and an indeterminate pterosaur. In the Herbert Sound Member of the Snow Hill Island Formation, bivalves, ammonites, and fish were found.O'Gorman, 2012, p.3 Fossil content See also * List of fossiliferous stratigraphic units in Antarctica * List of dinosaur-bearing rock formations * So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraves
Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosaurids, troodontids, anchiornithids, and possibly the scansoriopterygids, the group also contains the avialans, among which are the over ten thousand species of living birds. Early members of Paraves are well known for the possession of an enlarged claw on the second digit of the foot, which was held off the ground when walking in some species. Description Like other theropods, all paravians are bipedal, walking on their two hind legs. The teeth of primitive paravians were curved and serrated, but not blade-like except in some specialized species such as ''Dromaeosaurus albertensis''. The serrations on the front edge of dromaeosaurid and troodontid teeth were very small and fine, while the back edge had serrations which were very large and hooked. Most of the earliest paravian groups were carnivorous, though some smaller species (especially a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Ross Island
James Ross Island is a large island off the southeast side and near the northeastern extremity of the Antarctic Peninsula, from which it is separated by Prince Gustav Channel. Rising to , it is irregularly shaped and extends in a north–south direction. It was charted in October 1903 by the Swedish Antarctic Expedition under Otto Nordenskiöld, who named it for Sir James Clark Ross, the leader of a British expedition to this area in 1842 that discovered and roughly charted a number of points along the eastern side of the island. The style, "James" Ross Island is used to avoid confusion with the more widely known Ross Island in McMurdo Sound. It is one of several islands around the peninsula known as Graham Land, which is closer to South America than any other part of that continent. The island was connected to the Antarctic mainland by an ice shelf until 1995, when the ice shelf collapsed, making the Prince Gustav Channel passable for the first time. Mendel Polar Station, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where vegetation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length
Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the International System of Units (SI) system the base unit for length is the metre. Length is commonly understood to mean the most extended dimension of a fixed object. However, this is not always the case and may depend on the position the object is in. Various terms for the length of a fixed object are used, and these include height, which is vertical length or vertical extent, and width, breadth or depth. Height is used when there is a base from which vertical measurements can be taken. Width or breadth usually refer to a shorter dimension when length is the longest one. Depth is used for the third dimension of a three dimensional object. Length is the measure of one spatial dimension, whereas area is a measure of two dimensions (length square ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantism
Gigantism ( el, γίγας, ''gígas'', "giant", plural γίγαντες, ''gígantes''), also known as giantism, is a condition characterized by excessive growth and height significantly above average. In humans, this condition is caused by over-production of growth hormone in childhood, resulting in people up to in height. It is a rare disorder resulting from increased levels of growth hormone before the fusion of the growth plate which usually occurs at some point soon after puberty. This increase is most often due to abnormal tumor growths on the pituitary gland. Gigantism should not be confused with acromegaly, the adult form of the disorder, characterized by somatic enlargement specifically in the extremities and face. Cause Gigantism is characterized by an excess of growth hormone (GH). The excess of growth hormone that brings about gigantism is virtually always caused by pituitary growths (adenomas). These adenomas are on the anterior pituitary gland. They can also ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genera
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 clearly demons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Austroraptor
''Austroraptor'' ( ) is a genus of large dromaeosaurid dinosaur that lived during the Late Cretaceous Period in what is now Argentina. ''Austroraptor'' was a large-sized, moderately-built, ground-dwelling, bipedal carnivore, estimated at in length. It is one of the largest dromaeosaurids known, with only ''Achillobator'', ''Dakotaraptor'', and ''Utahraptor'' approaching or surpassing it in length. Discovery and naming The type specimen of ''Austroraptor cabazai'', holotype MML-195, was recovered in the Bajo de Santa Rosa locality of the Allen Formation, in Río Negro, Argentina. The specimen was collected in 2002 by the team of Fernando Emilio Novas of the '' Museo Argentino de Ciencias Naturales''. It consists of a fragmentary skeleton including parts of the skull, lower jaw, a few neck and torso vertebrae, some ribs, a humerus, and assorted bones from both legs. The specimen was prepared by Marcelo Pablo Isasi and Santiago Reuil. In 2008, the type species ''Austroraptor cab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from . The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene). The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) occurred at the end of this age. In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about wide colliding with Earth, ending the Cretaceous. Stratigraphic definitions Definition The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the Chalk Group c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deinonychus
''Deinonychus'' ( ; ) is a genus of dromaeosaurid theropod dinosaur with one described species, ''Deinonychus antirrhopus''. This species, which could grow up to long, lived during the early Cretaceous Period, about 115–108 million years ago (from the mid-Aptian to early Albian stages). Fossils have been recovered from the U.S. states of Montana, Utah, Wyoming, and Oklahoma, in rocks of the Cloverly Formation, Cedar Mountain Formation and Antlers Formation, though teeth that may belong to ''Deinonychus'' have been found much farther east in Maryland. Paleontologist John Ostrom's study of ''Deinonychus'' in the late 1960s revolutionized the way scientists thought about dinosaurs, leading to the " dinosaur renaissance" and igniting the debate on whether dinosaurs were warm-blooded or cold-blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. Ostrom noted the small body, sleek, horizontal posture, ratite-like spine, and esp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars (including its own descendants, the Romance languages) supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition. Latin is a highly inflected language, with three distinct genders (masculine, feminine, and neuter), six or seven noun cases (nominative, accusative, genitive, dative, ablative, and vocative), five declensions, four verb conjuga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
