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Dinosaur Paleobiogeography
Dinosaur paleobiogeography is the study of dinosaur geographic distribution, based on evidence in the fossil record. Late Cretaceous North America Thomas M. Lehman, in a study of Late Cretaceous dinosaur distribution, concluded that they were "remarkably provincial," with herbivorous dinosaurs exhibiting "persistent latitudinal and altitudinal zonation" in " stinctive endemic associations." Provincialism was even present during the turbulent faunal turnover of the Maastrichtian stage, when the Laramide Orogeny triggered "the most dramatic event that affected Late Cretaceous dinosaur communities in North America prior to their extinction." This turnover event saw specialized and highly ornamented centrosaurines and lambeosaurines be replaced by more primitive upland dinosaurs in the south while northern biomes became dominated by ''Triceratops'' with a greatly reduced hadrosaur community. Judithian Faunal Stage Many dinosaur species in North America during the Late Cretaceous had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrosaurus BW
''Centrosaurus'' ( ; ) is a genus of herbivorous ceratopsian dinosaur from the Late Cretaceous of Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago. Discovery and naming The first ''Centrosaurus'' remains were discovered and named by paleontologist Lawrence Lambe in strata along the Red Deer River in Alberta, Canada. The name ''Centrosaurus'' means "pointed lizard" (from Greek ', , "point or prickle" and ', , "lizard"), and refers to the series of small hornlets placed along the margin of their frills, not to the nasal horns (which were unknown when the dinosaur was named). The genus is not to be confused with the stegosaur ''Kentrosaurus'', the name of which is derived from the same Greek word. Later, vast bonebeds of ''Centrosaurus'' were found in Dinosaur Provincial Park, also in Alberta. Some of these beds extend for hundreds of meters and contain thousands of individuals of all ages and all levels of completi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentaceratops
''Pentaceratops'' ("five-horned face") is a genus of herbivorous ceratopsid dinosaur from the late Cretaceous Period of what is now North America. Fossils of this animal were first discovered in 1921, but the genus was named in 1923 when its type species, ''Pentaceratops sternbergii'', was described. ''Pentaceratops'' lived around 76–73 million years ago, its remains having been mostly found in the Kirtland Formation in the San Juan County, New Mexico, San Juan Basin in New Mexico. About a dozen skulls and skeletons have been uncovered, so anatomical understanding of ''Pentaceratops'' is fairly complete. One exceptionally large specimen later became its own genus, ''Titanoceratops'', due to its more derived morphology, similarities to ''Triceratops,'' and lack of unique characteristics shared with ''Pentaceratops''. ''Pentaceratops'' was about 6 meters (20 feet) long, and has been estimated to have weighed around . It had a short nose horn, two long brow horns, and long horns o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Medicine Formation
The Two Medicine Formation is a geological formation, or rock body, in northwestern Montana and southern Alberta that was deposited between and (million years ago), during Campanian (Late Cretaceous) time. It crops out to the east of the Rocky Mountain Overthrust Belt, and the western portion (about thick) of this formation is folded and faulted while the eastern part, which thins out into the Sweetgrass Arch, is mostly undeformed plains. Below the formation are the nearshore (beach and tidal zone) deposits of the Virgelle Sandstone, and above it is the marine Bearpaw Shale. Throughout the Campanian, the Two Medicine Formation was deposited between the western shoreline of the Late Cretaceous Interior Seaway and the eastward advancing margin of the Cordilleran Overthrust Belt. The Two Medicine Formation is mostly sandstone, deposited by rivers and deltas. History of research In 1913 in paleontology, 1913, a US Geological Survey crew headed by Eugene Stebinger and a US Nationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclonius
''Monoclonius'' (meaning "single sprout") is a dubious genus of herbivorous ceratopsian dinosaur found in the Late Cretaceous layers of the Judith River Formation in Montana, United States, and the uppermost rock layers of the Dinosaur Park Formation in Alberta, Canada dated to between 75 and 74.6 million years ago. ''Monoclonius'' was named by Edward Drinker Cope in 1876. Later, much taxonomic confusion was caused by the discovery of ''Centrosaurus'', a very similar genus of ceratopsian that is known from much better remains. Today, typical ''Monoclonius'' specimens are usually believed to be juveniles or subadults, in many cases of other genera such as ''Centrosaurus''. Those specimens that remain under the name ''Monoclonius'' are mostly too incomplete or immature to be confidently matched with adult specimens from the same time and place. This is especially true of the type species, ''Monoclonius crassus''. Therefore, ''Monoclonius'' is now usually considered a '' nomen dubiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normapolles
''Normapolles'' is an extinct angiosperm pollen group that arose in the Cenomanian (Late Cretaceous). ''Normapolles'' persisted until the early Oligiocene Epoch (Tertiary Period) but were reduced in diversity by the early Eocene Epoch. ''Normapolles'' were widespread in the Late Cretaceous of southern and eastern North America and Europe up to the West Siberian Plain between 56°N and 36°N, collectively referred to as the "''Normapolles'' Province". ''Normapolles'' is characterized by a triangular amb and an internally complex tricolpate pore structure with deep pore canals “oblate, mostly triporate or brevitricolp(or)ate pollen having complex, commonly protruding apertures and typically a triangular amb, although some are more or less circular in polar view.” Over 160 genera have been described as part of the ''Normapolles'' complex. ''Normapolles'' grains have been found inside fossilized flowers of the walnut family (Juglandaceae The Juglandaceae are a plant family know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquillapollenites
''Aquillapollenites'' is an extinct morphogenus of Late Cretaceous angiosperm pollen grain. ''Aquillapollenites'' was a very large group containing something like 80 total species, but all of them were typified by their triprojectate structure: three processes extend from the equator of the pollen grain and one process extends upwards to each pole, giving ''Aquillapollenites'' the shape of a child's jack. This strange shape may improve the buoyancy of the pollen grain. Colpi occupy each terminus of the equatorial projectates, making ''Aquillapollenites'' tricolporate. ''Aquillapollenities'' was mostly extinct by the end of the Cretaceous, but a few species survive across the K-T boundary into the Eocene Epoch. North America's northern animal biome approximately correspond with the ''Aquillapollenites'' palynofloral province.Lehman, T. M., 2001, Late Cretaceous dinosaur provinciality: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachyrhinosaurus
''Pachyrhinosaurus'' (meaning in Greek "thick-nosed lizard", from ' (), thick; ' (), nose; and (), lizard) is an extinct genus of centrosaurine ceratopsid dinosaur from the Late Cretaceous period of North America. The first examples were discovered by Charles M. Sternberg in Alberta, Canada, in 1946, and named in 1950. Over a dozen partial skulls and a large assortment of other fossils from various species have been found in Alberta and Alaska. A great number were not available for study until the 1980s, resulting in a relatively recent increase of interest in ''Pachyrhinosaurus''. Three species have been identified. ''P. lakustai'', from the Wapiti Formation, the bonebed horizon of which is roughly equivalent age to the upper Bearpaw and lower Horseshoe Canyon Formations, is known to have existed from about 73.5–72.5 million years ago. ''P. canadensis'' is younger, known from the lower Horseshoe Canyon Formation, about 71.5–71 Ma ago and the St. Mary River Formation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submontane
Foothills or piedmont are geographically defined as gradual increases in elevation at the base of a mountain range, higher hill range or an upland area. They are a transition zone between plains and low relief hills and the adjacent topographically higher mountains, hills, and uplands. Frequently foothills consist of alluvial fans, coalesced alluvial fans, and dissected plateaus. Description Foothills primarily border mountains, especially those which are reached through low ridges that increase in size closer and closer to the mountain, but can also border uplands and higher hills. Examples Areas where foothills exist, or areas commonly referred to as the foothills, include the: *Sierra Nevada foothills of California, USA *Foothills of the San Gabriel Valley in Los Angeles County, California, USA *Rocky Mountain Foothills in British Columbia and Alberta, Canada *Silesian Foothills in Silesia, Poland *Sivalik Hills along the Himalayas in the Indian subcontinent * Catalin ... [...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] |
Scientific Literature
: ''For a broader class of literature, see Academic publishing.'' Scientific literature comprises scholarly publications that report original empirical and theoretical work in the natural and social sciences. Within an academic field, scientific literature is often referred to as the literature. Academic publishing is the process of contributing the results of one's research into the literature, which often requires a peer-review process. Original scientific research published for the first time in scientific journals is called the primary literature. Patents and technical reports, for minor research results and engineering and design work (including computer software), can also be considered primary literature. Secondary sources include review articles (which summarize the findings of published studies to highlight advances and new lines of research) and books (for large projects or broad arguments, including compilations of articles). Tertiary sources might include encyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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