|
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] |
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] |
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] |
Corythosaurus
''Corythosaurus'' (; ) is a genus of hadrosaurid "duck-billed" dinosaur from the Upper Cretaceous Period (geology), Period, about 77–75.7 million years ago. It lived in what is now North America. Its name means "helmet lizard", derived from Ancient Greek, Greek κόρυς. It was named and described in 1914 by Barnum Brown. ''Corythosaurus'' is now thought to be a Lambeosaurinae, lambeosaurine, related to ''Nipponosaurus'', ''Velafrons'', ''Hypacrosaurus'', and ''Olorotitan''. ''Corythosaurus'' has an estimated length of , and has a skull, including the crest, that is tall. ''Corythosaurus'' is known from many complete specimens, including the nearly complete holotype found by Brown in 1911. The holotype skeleton is only missing the last section of the tail, and part of the forelimbs, but was preserved with impressions of polygonal scales. ''Corythosaurus'' is known from many skulls with tall crests. The crests resemble the crests of the cassowary and a Corinthian helmet. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrosaurus
''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 complet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the int ... [...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] |
Biome
A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader term than habitat and can comprise a variety of habitats. While a biome can cover large areas, a microbiome is a mix of organisms that coexist in a defined space on a much smaller scale. For example, the human microbiome is the collection of bacteria, viruses, and other microorganisms that are present on or in a human body. A biota is the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales. The biotas of the Earth make up the biosphere. Etymology The term was suggested in 1916 by Clements, originally as a synonym for '' biotic community'' of Möbius (1877). Later, it gained its c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., it borders the Canadian province of British Columbia and the Yukon territory to the east; it also shares a maritime border with the Russian Federation's Chukotka Autonomous Okrug to the west, just across the Bering Strait. To the north are the Chukchi and Beaufort Seas of the Arctic Ocean, while the Pacific Ocean lies to the south and southwest. Alaska is by far the largest U.S. state by area, comprising more total area than the next three largest states (Texas, California, and Montana) combined. It represents the seventh-largest subnational division in the world. It is the third-least populous and the most sparsely populated state, but by far the continent's most populous territory located mostly north of the 60th parallel, with ... [...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] |
Ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes. Ecosystems are controlled by external and internal factors. External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. ... [...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] |
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An unrooted tree diagram (a network) makes no assumption about the ancestral line, and does ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Pentaceratops")
