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Variodens
''Variodens'' is an extinct genus of trilophosaur. Fossils have been found from the Emborough Quarries in the Mendip Hills of Somerset, England. These fossils have been uncovered from a Late Triassic fissure fill within Carboniferous-age limestone. The type and only known species is ''V. inopinatus'', named in 1957. Description ''Variodens'' is unusual among most reptiles in that it has a heterodont dentition consisting of different types of teeth. The five anteriormost teeth at the front of the jaw are simple and conical in shape. The cheek teeth toward the back of the jaw are wide and have several cusps. They are either tricuspid or multicuspid. The anterior tricuspid teeth of ''Variodens'' are narrower medially (toward the inside of the mouth) than they are laterally (toward the outside of the mouth). ''Variodens'' also has distinctive bulbous-shaped penultimate teeth. The teeth of ''Variodens'' are very similar to the postcanine teeth of the cynodont ''Cricodon'' from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricuspisaurus
''Tricuspisaurus'' is an extinct genus of reptile originally described as a trilophosaurid; it was later considered likely to be a procolophonid, but recent analyses have affirmed the original classification. Fossils are known from the Ruthin Quarry in Glamorgan, Wales, one of several Late Triassic to Early Jurassic British fissure deposits. Like some trilophosaurs, it has an edentulous, or toothless beak. ''Tricuspisaurus'' gets its name from its heterodont dentition, which includes ''tricuspid'' teeth, or teeth with three cusps. The type species, ''T. thomasi'', was named in 1957 along with the possible trilophosaur '' Variodens inopinatus'' from Somerset, England. Although originally classified as a trilophosaur, ''Tricuspisaurus'' was reclassified as a procolophonid in 1993 by paleontologists Hans-Dieter Sues and Paul E. Olsen Paul E. Olsen (born August 4, 1953) is an American paleontologist and author and co-author of a large number of technical papers. Growing up as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilophosaur
Trilophosaurs are lizard-like Triassic allokotosaur reptiles related to the archosaurs. The best known genus is ''Trilophosaurus'', a herbivore up to long. It had a short, unusually heavily built skull, equipped with massive, broad flattened cheek teeth with sharp shearing surfaces for cutting up tough plant material. Teeth are absent from the premaxilla and front of the lower jaw, which in life were probably equipped with a horny beak. The skull is also unusual in that the lower temporal opening is missing, giving the appearance of a euryapsid skull, and originally the Trilophosaurs were classified with placodonts and sauropterygia. Carroll (1988) suggests that the lower opening may have been lost to strengthen the skull. Trilophosaurs are so far known only from the Late Triassic of North America and Europe. Below is a cladogram showing the phylogenetic relationships of Trilophosauridae within Archosauromorpha Archosauromorpha (Greek for "ruling lizard forms") is a cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, Ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful sandstone'')'', t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penultimate Tooth
Penult is a linguistics term for the second to last syllable of a word. It is an abbreviation of ''penultimate'', which describes the next-to-last item in a series. The penult follows the antepenult and precedes the ultima. For example, the main stress falls on the penult in such English words as ''banána'', and ''Mississíppi'', and just about all words ending in –ic such as músic, frántic, and phonétic. Occasionally, "penult" refers to the last word but one of a sentence. The terms are often used in reference to languages like Latin and Ancient Greek, where the position of the pitch accent or stress of a word only falls on one of the last three syllables, and sometimes in discussing poetic meter. In certain languages, such as Welsh and Polish, stress is always on the penult. in the World Atlas of Language S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans-Dieter Sues
Hans-Dieter Sues (born January 13, 1956) is a German-born American paleontologist who is Senior Scientist and Curator of Vertebrate Paleontology at the National Museum of Natural History of the Smithsonian Institution in Washington, DC. He received his education at Johannes Gutenberg-Universität Mainz (University of Mainz), University of Alberta, and Harvard University (Ph.D., 1984). Before assuming his present position, Sues worked at the Royal Ontario Museum and the University of Toronto and at the Carnegie Museum of Natural History in Pittsburgh. He is interested in the diversity, paleoecology, and evolutionary history of Paleozoic and Mesozoic tetrapods, especially archosaurian reptiles and cynodont therapsids, and the history of biology and paleontology. Sues has discovered numerous new dinosaurs and other extinct terrestrial vertebrates in Paleozoic and Mesozoic continental strata in North America and Europe. He has authored or co-authored over 150 articles and book chapte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moenkopi Formation
The Moenkopi Formation is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona. Part of the Colorado Plateau and Basin and Range, this red sandstone was laid down in the Lower Triassic and possibly part of the Middle Triassic, around 240 million years ago. History of investigation There is no designated type locality for this formation. It was named for a development at the mouth of Moencopie Wash in the Grand Canyon area by Ward in 1901. In 1917 a 'substitute' type locality was located by Gregory in the wall of the Little Colorado Canyon, about 5 miles below Tanner Crossing in Coconino County, Arizona. While in the Great Basin, Bassler and Reeside characterized and named the Rock Canyon Conglomerate, Virgin Limestone, and Shnabkaib Shale members in 1921. Salt Creek (later replaced by Wupatki and Moqui Members) and the H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisodontosaurus
''Anisodontosaurus'' is an extinct genus of trilophosaurid allokotosaur known from the Middle Triassic Moenkopi Formation of Arizona. The type species, ''A. greeri'', was named and described by Samuel Paul Welles in 1947,S. P. Welles. 1947. Vertebrates from the Upper Moenkopi Formation of northern Arizona. ''University of California Publications in Geological Sciences'' 27(7):241-294 and its taxonomic placement was largely unknown (placed within the Eosuchia by Welles in 1947) until the holotype was reassessed in 1988, when it was recovered as a lepidosauromorph Lepidosauromorpha (in PhyloCode known as ''Pan-Lepidosauria'') is a group of reptiles comprising all diapsids closer to lizards than to archosaurs (which include crocodiles and birds). The only living sub-group is the Lepidosauria, which contains ... or a trilophosaurid. The holotype, a jaw catalogued as UCMP V3922, was discovered in 1940 and was described seven years later. Apart from the type specimen, ''Anisodontosaur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dockum Group
The Dockum is a Late Triassic (approximately late Carnian through Rhaetian, or 223–200 Ma) geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much thinner. The Dockum rests on an unconformity over the Anisian (242–234 Ma) aged Anton Chico Formation. The Dockum and Chinle Formation were deposited roughly at the same time and share many of the same vertebrates and plant fossils. They appear to have very similar paleoenviroments. The two units are approximately separated by the Rio Grande in central New Mexico. This has led to controversy over the stratigraphic nomenclature for the Chinle and Dockum. History of investigation There is no designated type locality for this formation. The Dockum was named by William Fletcher Cummins for a good exposure in vicinity of town ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edentulism
Toothlessness, or edentulism, is the condition of having no teeth. In organisms that naturally have teeth, it is the result of tooth loss. Organisms that never possessed teeth can also be described as edentulous. Examples are the members of the former zoological classification order of '' Edentata'', which included anteaters and sloths, as they possess no anterior teeth and no or poorly developed posterior teeth. In naturally dentate species, edentulism is more than just the simple presence or absence of teeth. It is biochemically complex because the teeth, jaws, and oral mucosa are dynamic (changing over time). Processes such as bone remodeling (loss and gain of bone tissue) in the jaws and inflammation of soft tissue in response to the oral microbiota are clinically important for edentulous people. For example, bone resorption in the jaw is frequently how the teeth were able to detach in the first place; the jaw in an edentulous area undergoes further resorption even aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical Omani Empire and colonial territories of the British East Africa Protectorate and German East Africa, the term ''East Africa'' is often (especially in the English language) used to specifically refer to the area now comprising the three countries of Kenya, Tanzania, and Uganda. However, this has never been the convention in many other languages, where the term generally had a wider, strictly geographic context and therefore typically included Djibouti, Eritrea, Ethiopia, and Somalia.Somaliland is not included in the United Nations geoscheme, as it is internationally recognized as a part of Somalia. *Tanzania, Kenya, Uganda, Rwanda, Burundi, Democratic Republic of Congo and South Sudan are members of the East African Community. The firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manda Formation
The Manda Formation (also known as the Manda Beds) is a Middle Triassic (Anisian?) or possibly Late Triassic (Carnian?) geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Triassic, including some of the earliest dinosauromorph archosaurs. The formation is often considered to be Anisian in age according to general tetrapod biochronology hypotheses and correlations to the ''Cynognathus'' Assemblage Zone of South Africa. However, some recent studies cast doubt to this age, suggesting that parts deposits may actually be younger (Carnian) in age. History of study One of the first to study rocks of the Manda Formation was British geologist G. M. Stockley. In 1932, Stockley explored the geology of the Ruhuhu Basin in Tanzania. He called a series of layers dating from the Late Carboniferous to the Middle Triassic the Songea Series and divided it into eight units labelled K1-K8. Stockley was also the first to describe fossils from these rocks, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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