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Antarctopelta
''Antarctopelta'' (; meaning 'Antarctic shield') is a genus of ankylosaurian dinosaur, a group of large, quadrupedal herbivores, that lived during the Campanian stage of the Late Cretaceous period on what is now James Ross Island, Antarctica. ''Antarctopelta'' is the only known ankylosaur from Antarctica and a member of Parankylosauria. The only described specimen was found in 1986, the first dinosaur to be found on the continent, by Argentines, Argentine Geologist, geologists Eduardo Olivero and Robert Scasso. The fossils were later described in 2006 by paleontologists Leonardo Salgado and Zulma Gasparini, who named the type species ''A. oliveroi'' after Olivero. It was a medium-sized ankylosaur, reaching in length or more, and showed characteristics of two different families, making more precise classification difficult for many years. This was until 2021, when a nearly complete skeleton of the similar Chile, Chilean genus ''Stegouros'' was described. This led to the recogniti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian spans the time from 83.6 (± 0.2) to 72.1 (± 0.2) million years ago. It is preceded by the Santonian and it is followed by the Maastrichtian. The Campanian was an age when a worldwide sea level rise covered many coastal areas. The morphology of some of these areas has been preserved: it is an unconformity beneath a cover of marine sedimentary rocks. Etymology The Campanian was introduced in scientific literature by Henri Coquand in 1857. It is named after the French village of Champagne in the department of Charente-Maritime. The original type locality was a series of outcrop near the village of Aubeterre-sur-Dronne in the same region. Definition The base of the Campanian Stage is defined as a place in the stratigraphic column wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stegouros
''Stegouros'' (, meaning "roofed tail") is a genus of ankylosaurian dinosaur from the Late Cretaceous Dorotea Formation of southern Chile. The genus contains a single species, ''Stegouros elengassen'', known from a semi-articulated, near-complete skeleton. Discovery In February 2018, the skeleton of a small ankylosaur was recovered by a team of Texan researchers near the Río de las Chinas valley of Ultima Esperanza province in the Magallanes y la Antártica Chilena region of southern Chile. In 2021, the type species ''Stegouros elengassen'' was named and described by Sergio Soto-Acuña ''et al''. The generic name combines the Greek ''stegos'', meaning "roof" and ''oura'', meaning "tail", referring to the roof-like covering of the tail end. The specific name ''elengassen'' is derived from an armoured creature in the mythology of the Aónik’enk, the indigenous inhabitants of the region where the holotype was discovered. The holotype, CPAP-3165, was found in a layer of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Earliest Late Cretaceous with 42 described genera. During the last 20 million years of the Cretaceous period (Turonian–Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They themselves became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago. Description Mosasaurs breathed air, were powerful swimmers, and were well-adapted to living in the warm, shallow inland seas prevalent during the Late Cretaceous period. Mosasaurs were so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trinisaura
''Trinisaura'' is an extinct genus of ornithopod dinosaur known from the lower levels of the Late Cretaceous Snow Hill Island Formation (early Maastrichtian stage) of James Ross Island, Antarctica. It contains a single species, ''Trinisaura santamartaensis''. Discovery and naming The species was in 2013 named by Rodolfo Aníbal Coria e.a. The generic name honours the geologist Trinidad Diaz. The specific name refers to the Santa Marta Cove site where the specimen was in 2008 found by Coria and Juan José Moly. That same year, the find was reported in the scientific literature.Coria, R.A., Moly, J.J., Reguero, M., Santillana, S., 2008, "Nuevos restos de Ornithopoda (Dinosauria, Ornithischia) de la Fm. Santa Marta, Isla J. Ross, Antártida", ''Ameghiniana'' 45(4), Supl., 25R The holotype, MLP-III-1-1, consists of a partial skeleton lacking the skull, of a subadult individual about in length. Phylogeny The cladogram below follows Coria ''et al.'', 2013 phylogenetic analys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithopoda
Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, dominating the North American land. Their major evolutionary advantage was the progressive development of a chewing apparatus that became the most sophisticated ever developed by a non-avian dinosaur, rivaling that of modern mammals such as the domestic cow. They reached their apex of diversity and ecological dominance in the hadrosaurids (colloquially known as 'duck-bills'), before they were wiped out by the Cretaceous–Paleogene extinction event along with all other non-avian dinosaurs. Members are known from all seven continents, though they are generally rare in the Southern Hemisphere. History of research In 1870, Thomas Henry Huxley listed Iguanodontidae (coined by Cope a year earlier) as one of his three families of dinosaurs ( ... [...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] |
Macuahuitl
A macuahuitl () is a weapon, a wooden club with several embedded obsidian blades. The name is derived from the Nahuatl language and means "hand-wood". Its sides are embedded with prismatic blades traditionally made from obsidian. Obsidian is capable of producing an edge sharper than high quality steel razor blades. The macuahuitl was a standard close combat weapon. Use of the macuahuitl as a weapon is attested from the first millennium CE. By the time of the Spanish conquest the macuahuitl was widely distributed in Mesoamerica. The weapon was used by different civilisations including the Aztec (Mexicas), Maya, Mixtec and Toltec. One example of this weapon survived the Conquest of the Aztec Empire; it was part of the Royal Armoury of Madrid until it was destroyed by a fire in 1884. Images of the original designs survive in diverse catalogues. The oldest replica is the macuahuitl created by the medievalist Achille Jubinal in the 19th century. Description The maquahuitl ( n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoderm
Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amphibians), various groups of dinosaurs (most notably ankylosaurs and stegosaurians), phytosaurs, aetosaurs, placodonts, and hupehsuchians (marine reptiles with possible ichthyosaur affinities). Osteoderms are uncommon in mammals, although they have occurred in many xenarthrans (armadillos and the extinct glyptodonts and mylodontid and scelidotheriid ground sloths). The heavy, bony osteoderms have evolved independently in many different lineages. The armadillo osteoderm is believed to develop in subcutaneous dermal tissues. These varied structures should be thought of as anatomical analogues, not homologues, and do not necessarily indicate monophyly. The structures are however derived from scutes, common to all classes of amniotes and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross-sectional Study
In medical research, social science, and biology, a cross-sectional study (also known as a cross-sectional analysis, transverse study, prevalence study) is a type of observational study that analyzes data from a population, or a representative subset, ''at a specific point in time''—that is, cross-sectional data. In economics, cross-sectional studies typically involve the use of cross-sectional regression, in order to sort out the existence and magnitude of causal effects of one independent variable upon a dependent variable of interest at a given point in time. They differ from time series analysis, in which the behavior of one or more economic aggregates is traced through time. In medical research, cross-sectional studies differ from case-control studies in that they aim to provide data on the entire population under study, whereas case-control studies typically include only individuals who have developed a specific condition and compare them with a matched sample, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Vertebrae
In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae and they are intermediate in size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae, with the lower ones being much larger than the upper. They are distinguished by the presence of Zygapophysial joint, facets on the sides of the bodies for Articulation (anatomy), articulation with the head of rib, heads of the ribs, as well as facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the tubercle (rib), tubercles of the ribs. By convention, the human thoracic vertebrae are numbered T1–T12, with the first one (T1) located closest to the skull and the others going down the spine toward the lumbar region. General characteristics These are the general characteristics of the second throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cervical Vertebrae
In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The vertebral transverse processes of mammals are homologous to the cervical ribs of other amniotes. Most mammals have seven cervical vertebrae, with the only three known exceptions being the manatee with six, the two-toed sloth with five or six, and the three-toed sloth with nine. In humans, cervical vertebrae are the smallest of the true vertebrae and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which the vertebral artery, vertebral veins, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
