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Brachychampsa Montana
''Brachychampsa'' is an extinct genus of alligatoroid, possibly a basal caiman. Specimens have been reported from New Mexico, Colorado, Wyoming, Montana, North and South Dakota, New Jersey, and Saskatchewan, though only those from Montana, Utah, and New Mexico are based on material sufficient to justify the referral. One specimen has been reported from the Darbasa Formation of Kazakhstan, although the species status is indeterminate for the fossil. The genus first appeared during the late Campanian stage of the Late Cretaceous (Judithian North American stage) and became extinct during the late Maastrichtian stage of the Cretaceous (Lancian North American Land Mammal "Age"). ''Brachychampsa'' is distinguished by an enlarged fifth maxillary tooth in the upper jaw. Species The type species of ''Brachychampsa'' is ''B. montana'', first discovered from the Hell Creek Formation of Montana and described by Charles W. Gilmore in a paper in 1911. In that same paper, Gilmore recombine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saskatchewan
Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on the south by the United States, U.S. states of Montana and North Dakota. Saskatchewan and Alberta are the only landlocked provinces of Canada. In 2022, Saskatchewan's population was estimated at 1,205,119. Nearly 10% of Saskatchewan’s total area of is fresh water, mostly rivers, reservoirs and List of lakes in Saskatchewan, lakes. Residents primarily live in the southern prairie half of the province, while the northern half is mostly forested and sparsely populated. Roughly half live in the province's largest city Saskatoon or the provincial capital Regina, Saskatchewan, Regina. Other notable cities include Prince Albert, Saskatchewan, Prince Albert, Moose Jaw, Yorkton, Swift Current, North Battleford, Melfort, Saskatchewan, Melfort, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bottosaurus Perrugosus
''Bottosaurus'' is an extinct genus of alligatorid from the Late Cretaceous-Early Paleocene of New Jersey, Texas, and possibly North Carolina and South Carolina. Two species are currently accepted, with a third requiring re-evaluation. Taxonomy & Distribution Recent phylogenetic studies have recovered ''Bottosaurus'' as a member of Alligatoridae within the subfamily Caimaninae, which indicates that ''Bottosaurus'' is more closely related to caimans than to alligators. ''Bottosaurus harlani'' is predominantly found from Late Cretaceous strata of Maastrichtian age, such as the Hornerstown Formation and New Jersey Greensands. New material has been reported from the Rhems and Williamsburg Formations of the Black Mingo Group of the South Carolina coastal plain that dates back to the Danian and Thanetian stages of the Paleocene epoch, suggesting that ''Bottosaurus'' had survived the Cretaceous–Paleogene extinction event and lived through much of the early Paleogene period. However, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hell Creek Formation
The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of Montana, North Dakota, South Dakota, and Wyoming. In Montana, the Hell Creek Formation overlies the Fox Hills Formation. The site of Pompeys Pillar National Monument is a small isolated section of the Hell Creek Formation. In 1966, the Hell Creek Fossil Area was designated as a National Natural Landmark by the National Park Service. It is a series of fresh and brackish-water clays, mudstones, and sandstones deposited during the Maastrichtian and Danian (respectively, the end of the Cretaceous period and the beginning of the Paleogene) by fluvial activity in fluctuating river channels and deltas and very occasional peaty swamp deposits along the low-lying eastern continental margin fronting the late Cretaceous Western Interior Seaway. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachychampsa Sp
''Brachychampsa'' is an extinct genus of alligatoroid, possibly a basal caiman. Specimens have been reported from New Mexico, Colorado, Wyoming, Montana, North and South Dakota, New Jersey, and Saskatchewan, though only those from Montana, Utah, and New Mexico are based on material sufficient to justify the referral. One specimen has been reported from the Darbasa Formation of Kazakhstan, although the species status is indeterminate for the fossil. The genus first appeared during the late Campanian stage of the Late Cretaceous (Judithian North American stage) and became extinct during the late Maastrichtian stage of the Cretaceous (Lancian North American Land Mammal "Age"). ''Brachychampsa'' is distinguished by an enlarged fifth maxillary tooth in the upper jaw. Species The type species of ''Brachychampsa'' is ''B. montana'', first discovered from the Hell Creek Formation of Montana and described by Charles W. Gilmore in a paper in 1911. In that same paper, Gilmore recombine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachychampsa NT Small
''Brachychampsa'' is an extinct genus of alligatoroid, possibly a basal caiman. Specimens have been reported from New Mexico, Colorado, Wyoming, Montana, North and South Dakota, New Jersey, and Saskatchewan, though only those from Montana, Utah, and New Mexico are based on material sufficient to justify the referral. One specimen has been reported from the Darbasa Formation of Kazakhstan, although the species status is indeterminate for the fossil. The genus first appeared during the late Campanian stage of the Late Cretaceous (Judithian North American stage) and became extinct during the late Maastrichtian stage of the Cretaceous (Lancian North American Land Mammal "Age"). ''Brachychampsa'' is distinguished by an enlarged fifth maxillary tooth in the upper jaw. Species The type species of ''Brachychampsa'' is ''B. montana'', first discovered from the Hell Creek Formation of Montana and described by Charles W. Gilmore in a paper in 1911. In that same paper, Gilmore recombine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth distal to the canines, preceded by deciduous molars. Morphology There is always one large buccal cusp, especially so in the mandibular first premolar. The lower second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lancian
The Lancian was a North American faunal stage of the Late Cretaceous. It was the final stage of the Cretaceous period in North America, lasting from approximately 70.6 to 66 million years ago. Geology Terrestrial sedimentary strata from the Judithian to the Lancian are generally regressive throughout the entire sequence, so the preserved changes in fossil communities represent not only phylogenetic changes but ecological zones from the submontane habitats to near-sea level coastal habitats. Paleobiogeography By the Lancian, the crested hadrosaurs are no longer the dominant inhabitant of any province of western North America; the only remaining species was '' Hypacrosaurus''. Lehman records three surviving chasmosaurs, ''Triceratops,'' '' Torosaurus'' and ''Nedoceratops'', with the possibility of the recently discovered ''Ojoceratops, Regaliceratops and'' ''Bravoceratops''. It has recently been suggested that ''Triceratops'' and ''Torosaurus'' may be synonymous, though this is sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...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] |
Judithian
The Judithian was a North American faunal stage lasting from 83.5 to 70.6 million years ago. It overlaps with the Campanian global stage. Fauna Dinosaur faunas of the Judithian age may represent the peak of dinosaur evolution in North America. Hadrosaurs were universally the dominant herbivore of the period and comprised more than half of "a typical assemblage." This was also the period of greatest genetic diversity among large herbivorous dinosaurs. Just in Montana and Southern Alberta were ten genera of ceratopsians and ten genera of hadrosaurs. Paleobiogeography Thomas M. Lehman has observed that ''Corythosaurus'' and ''Centrosaurus'' haven't been discovered outside of southern Alberta even though they are the most abundant Judithian dinosaurs in the region. Large herbivores like the ceratopsians and hadrosaurs living in North America during the Late Cretaceous had "remarkably small geographic ranges" despite their large body size and high mobility. This restricted distributi ... [...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] |
