|
Laramidia
Laramidia was an island continent that existed during the Late Cretaceous period (99.6–66 Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island land mass separated from Appalachia to the east by the Western Interior Seaway. The seaway eventually shrank, split across the Dakotas, and retreated toward the Gulf of Mexico and the Hudson Bay. The masses joined, forming the continent of North America. Laramidia is named after the Laramide orogeny. The name was coined by J. David Archibald in 1996. Geography Laramidia stretched from modern-day Alaska to Mexico. The area is rich in dinosaur fossils. Tyrannosaurs, dromaeosaurids, troodontids, hadrosaurs, ceratopsians (including ''Kosmoceratops'' and ''Utahceratops''), pachycephalosaurs, and titanosaur sauropods are some of the dinosaur groups that lived on this landmass. A strong latitudinal climatic gradient existed on the landmass in the final 15 million years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmoceratops
''Kosmoceratops'' () is a genus of ceratopsid dinosaur that lived in North America about 76–75.9 million years ago during the Late Cretaceous period. Specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Escalante National Monument in 2006 and 2007, including an adult skull and postcranial skeleton and partial subadults. In 2010, the adult was made the holotype of the new genus and species ''Kosmoceratops richardsoni''; the generic name means "ornate horned face", and the specific name honors Scott Richardson, who found the specimens. The find was part of a spate of ceratopsian discoveries in the early 21st century, and ''Kosmoceratops'' was considered significant due to its elaborate skull ornamentation. ''Kosmoceratops'' had an estimated length of and a weight of . As a ceratopsid, it would have been quadrupedal with a heavily constructed skeleton. It had a triangular beak with a pointed tip and a blade-like nasal horn with a flattened up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appalachia (Mesozoic)
During most of the Late Cretaceous (100.5 to 66 million years ago) the eastern half of North America formed Appalachia (named for the Appalachian Mountains), an island land mass separated from Laramidia to the west by the Western Interior Seaway. This seaway had split North America into two massive landmasses due to a multitude of factors such as tectonism and sea-level fluctuations for nearly 40 million years. The seaway eventually expanded, divided across the Dakotas, and by the end of the Cretaceous, it retreated towards the Gulf of Mexico and the Hudson Bay. This left the island masses joined in the continent of North America as the Rocky Mountains rose. From the Cenomanian to the end of the Campanian ages of the Late Cretaceous, Appalachia was separated from the rest of North America. As the Western Interior Seaway retreated in the Maastrichtian, Laramidia and Appalachia eventually connected. Because of this, its fauna was isolated, and developed very differently from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrannosaurus Rex
''Tyrannosaurus'' is a genus of large theropod dinosaur. The species ''Tyrannosaurus rex'' (''rex'' meaning "king" in Latin), often called ''T. rex'' or colloquially ''T-Rex'', is one of the best represented theropods. ''Tyrannosaurus'' lived throughout what is now western North America, on what was then an island continent known as Laramidia. ''Tyrannosaurus'' had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the Upper Cretaceous period, 68 to 66 million years ago. It was the last known member of the tyrannosaurids and among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event. Like other tyrannosaurids, ''Tyrannosaurus'' was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, the forelimbs of ''Tyrannosaurus'' were short but unusually powerful for their size, and they had two clawed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachycephalosauria
Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachycephalosaurs lived during the Late Cretaceous Period, dating between about 85.8 and 65.5 million years ago. They are exclusive to the Northern Hemisphere, all of them being found in North America and Asia. They were all bipedal, herbivorous/omnivorous animals with thick skulls. Skulls can be domed, flat, or wedge-shaped depending on the species, and are all heavily ossified. The domes were often surrounded by nodes and/or spikes. Partial skeletons have been found of several pachycephalosaur species, but to date no complete skeletons have been discovered. Often isolated skull fragments are the only bones that are found. Candidates for the earliest known pachycephalosaur include ''Ferganocephale adenticulatum'' from Middle Jurassic Period strata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utahceratops
''Utahceratops'' is an extinct genus of ceratopsian dinosaur that lived approximately 76.4~75.5 million years ago during the Late Cretaceous period in what is now Utah. ''Utahceratops'' was a large-sized, robustly-built, ground-dwelling, quadrupedal herbivore, that could grow up to an estimated long. Discovery The genus name ''Utahceratops'', means "horned face from Utah", and is derived from the state of Utah and Greek words "keras" (κέρας) meaning "horn" and "ops" (ὤψ) referring to the "face". The specific name ''gettyi'', is derived from the name of Mike Getty, who discovered the holotype and has played a pivotal role in the recovery of fossils from the Grand Staircase–Escalante National Monument (GSENM). It was first named by Scott D. Sampson, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith and Alan L. Titus in 2010, and the type species is ''Utahceratops gettyi''. Description The holotype specimen UMNH VP 16784, cons ... [...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] |
Hadrosaurid
Hadrosaurids (), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which includes genera such as ''Edmontosaurus'' and '' Parasaurolophus'', was a common group of herbivores during the Late Cretaceous Period. Hadrosaurids are descendants of the Upper Jurassic/Lower Cretaceous iguanodontian dinosaurs and had a similar body layout. Hadrosaurs were among the most dominant herbivores during the Late Cretaceous in Asia and North America, and during the close of the Cretaceous several lineages dispersed into Europe, Africa, South America and Antarctica. Like other ornithischians, hadrosaurids had a predentary bone and a pubic bone which was positioned backwards in the pelvis. Unlike more primitive iguanodonts, the teeth of hadrosaurids are stacked into complex structures known as dental batteries, which acted as effectiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Interior Seaway
The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea, which existed from the early Late Cretaceous (100 million years ago) to the earliest Paleocene (66 Ma), connected the Gulf of Mexico, through the United States and Canada, to the Arctic Ocean. The two land masses it created were Laramidia to the west and Appalachia to the east. At its largest extent, it was deep, wide and over long. Origin and geology By Late-Cretaceous times, Eurasia and the Americas had separated along the south Atlantic, and subduction on the west coast of the Americas had commenced, resulting in the Laramide orogeny, the early phase of growth of the modern Rocky Mountains. The Western Interior Seaway may be seen as a downwarping of the continental crust ahead of the growing Laramide/Rockies mountain chain. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Year
A year or annus is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally recognized: spring, summer, autumn and winter. In tropical and subtropical regions, several geographical sectors do not present defined seasons; but in the seasonal tropics, the annual wet and dry seasons are recognized and tracked. A calendar year is an approximation of the number of days of the Earth's orbital period, as counted in a given calendar. The Gregorian calendar, or modern calendar, presents its calendar year to be either a common year of 365 days or a leap year of 366 days, as do the Julian calendars. For the Gregorian calendar, the average length of the calendar year (t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrannosaurinae
The tyrannosaurines (Tyrannosaurinae) is an extinct subfamily of Tyrannosauridae a family of coelurosaurian theropod dinosaurs that consists of at least three tribes and several genera. All fossils of these genera have been found in the Late Cretaceous deposits of western North America and east Asia. Compare to the related subfamily Albertosaurinae, tyrannosaurines overall are more robust and larger though the alioramins were gracile by comparison. This subfamily also includes the oldest known tyrannosaurid genus ''Lythronax'' as well as the youngest and most famous member of the group, ''Tyrannosaurus rex''. History of discovery The first remains of tyrannosaurids were uncovered during expeditions led by the Geological Survey of Canada, which located numerous scattered teeth. These distinctive dinosaur teeth were given the name ''Deinodon'' ("terrible tooth") by Joseph Leidy in 1856. In 1892 Edward Drinker Cope described more tyrannosaur material in the form of isolated vertebra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrannosaur
Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic ''Tyrannosaurus''. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe and Asia, with fragmentary remains possibly attributable to tyrannosaurs also known from South America and Australia. Tyrannosauroids were bipedal carnivores, as were most theropods, and were characterized by numerous skeletal features, especially of the skull and pelvis. Early in their existence, tyrannosauroids were small predators with long, three-fingered forelimbs. Late Cretaceous genera became much larger, including some of the largest land ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene Ice Age
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing a faunal interchange between the two reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
