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Ankylosaurus
''Ankylosaurus'' is a genus of Thyreophora, armored dinosaur. Its fossils have been found in geological formations dating to the very end of the Cretaceous Period (geology), Period, about 68–66 million years ago, in western North America, making it among the last of the non-avian dinosaurs. It was named by Barnum Brown in 1908; it is Monotypic taxon, monotypic, containing only ''A. magniventris''. The Binomial nomenclature, generic name means "fused" or "bent lizard", and the specific name means "great belly". A handful of specimens have been excavated to date, but a complete skeleton has not been discovered. Though other members of Ankylosauria are represented by more extensive fossil material, ''Ankylosaurus'' is often considered the archetype, archetypal member of its group, despite having some unusual features. Possibly the largest known Ankylosauridae, ankylosaurid, ''Ankylosaurus'' is estimated to have been between long and to have weighed between . It was Quadrupedal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankylosauria
Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are known to have first appeared in North Africa during the Middle Jurassic, and persisted until the end of the Late Cretaceous. The two main families of ankylosaurians, Nodosauridae and Ankylosauridae primarily originated from the Northern Hemisphere (North America, Europe and Asia), but the more basal Parankylosauria originated from southern Gondwana (South America, Australia and Antarctica) during the Cretaceous. Ankylosauria was first named by Henry Fairfield Osborn in 1923.Osborn, H. F. (1923). "Two Lower Cretaceous dinosaurs of Mongolia." ''American Museum Novitates'', 95: 1–1/ref> In the Linnaean classification system, the group is usually considered either a suborder or an infraorder. It is contained within the group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent 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, Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Club (anatomy)
In zoology, a tail club is a bony mass at the end of the tail of some dinosaurs and of some mammals, most notably the Ankylosauridae, ankylosaurids and the glyptodonts, as well as meiolaniid turtles. It is thought that this was a form of defensive Armour (zoology), armour or weapon that was used to defend against predators, much in the same way as a thagomizer, possessed by stegosaurids, though at least in glyptodonts it is hypothesized it was used in Display (zoology), fighting for mating rights. Among dinosaurs, the club was present mainly in ankylosaurids, although Sauropoda, sauropods like ''Shunosaurus'' and ''Kotasaurus'' also possessed a tail club. Victoria Arbour has established that ankylosaurid tails could generate enough force to break bone during impacts. In a separate study, Arbour suggested tail clubs as well as large armoured herbivores as a whole evolve when animals are too large to hide and too small to avoid predation by size alone. Morphology In ankylosaurid di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecological Niche
In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of Resource (biology), resources and competitors (for example, by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (for example, limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey). "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another [and] the relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts". See also Chapter 2: Concepts of niches, pp. 7 ''ff'' A Grinnellian niche is determined by the habitat in which a species lives and its accompanying Behavioral ecology, behavioral adaptations. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the sister taxon to the Ankylosauridae, some analyses recover it as a paraphyletic grade leading to the ankylosaurids. Description Nodosaurids, like their sister group the ankylosaurids, were heavily armored dinosaurs adorned with rows of bony armor nodules and spines (osteoderms), which were covered in keratin sheaths. Ankylosaurians were small- to large-sized, heavily built, quadrupedal, herbivorous dinosaurs, possessing small, leaf-shaped teeth. Unlike ankylosaurids, nodosaurids lacked mace-like tail clubs and instead had more flexible tail tips. Many nodosaurids had spikes projecting outward from their shoulders. One particularly well-preserved nodosaurid "mummy", the holotype of '' Borealopelta markmitchelli'', preserves a nearly comple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denversaurus
''Denversaurus'' (meaning "Denver lizard") is a genus of panoplosaurin nodosaurid dinosaur from the late Maastrichtian of Late Cretaceous Western North America. Although at one point treated as a junior synonym of '' Edmontonia'' by some taxonomists, current research indicates that it is its own distinct nodosaurid genus. Discovery and naming In 1986, the paleontologists Kenneth Carpenter and Brent Breithaupt described DMNH 468 which was a specimen of a late Maastrichtian nodosaurid, tentatively assigned to '' Edmontonia'' sp., discovered from the lower Hell Creek Formation of South Dakota. In 1988, Robert Thomas Bakker decided to split the genus ''Edmontonia''. The species ''Edmontonia rugosidens'' was made into a separate genus named ''Chassternbergia'' and DMNH 468 was designated as a holotype of a new genus and species. The type species of this genus was ''Denversaurus schlessmani''. The generic name referred to the Denver Museum of Natural History at Denver, Colorado ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferris Formation
The Ferris Formation is a Late Cretaceous (~66 Ma) to Paleocene (66-63 Ma), fluvial-deltaic geological formation in southern Wyoming. It contains a variety of trace and body fossils, preserved in sandy fluvial channel deposits and overbank units. Dinosaur remains are fragmentary, but include ''Triceratops'', ''Tyrannosaurus'', dromaeosaurids, '' Paronychodon'', '' Ricardoestesia'', '' Edmontosaurus'', '' Edmontonia'', '' Ankylosaurus'', and '' Pachycephalosaurus''.Wroblewski, 1995 Some of the fluvial channels contain evidence of tidal influence and brackish water, in the form of tidal facies, shark teeth, and shrimp burrows. This demonstrates that the western shoreline of the Western Interior Sea was still within a few hundred kilometers even during the latest Cretaceous. The local K-T boundary is contained within a sandy channel deposit made up of stacked bars. Reworked Cretaceous fossils are preserved at the base of the channel complex, associated with mud rip-up clasts, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frenchman Formation
The Frenchman Formation is a stratigraphic unit of Late Cretaceous (late Maastrichtian) Geochronology, age in the Western Canadian Sedimentary Basin, Western Canada Sedimentary Basin. It is present in southern Saskatchewan and the Cypress Hills (Canada), Cypress Hills of southeastern Alberta. The formation was defined by G.M. Furnival in 1942 from observations of outcrops along the Frenchman River, between Ravenscrag, Saskatchewan, Ravenscrag and Saskatchewan Highway 37, Highway 37. It contains the youngest of dinosaur genera, much like the Hell Creek Formation in the United States. Lithology The Frenchman Formation consists of olive-green to brown, fine- to coarse-grained, cross-bedded sandstone with interbedded claystone bands and minor beds and lenses of intraformational clay-clast Conglomerate (geology), conglomerate. A conglomerate layer with well-rounded quartzite pebbles is present above the basal unconformity in some areas.Glass, D.J., editor, 1997. Lexicon of Canadian Str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scollard Formation
The Scollard Formation is an Upper Cretaceous to lower Palaeocene stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. Its deposition spanned the time interval from latest Cretaceous to early Paleocene, and it includes sediments that were deposited before, during, and after the Cretaceous-Paleogene (K-Pg) extinction event. It is significant for its fossil record, and it includes the economically important coal deposits of the Ardley coal zone. Lithology The Scollard Formation consists primarily of sandstones and siltstones, interbedded with mudstones and, in the upper portion, coal seams, as well as minor amounts of bentonite. The sediments were eroded from the Canadian Cordillera, and were transported eastward by river systems and deposited in fluvial channel and floodplain environments. Stratigraphy The Scollard is usually classified as the uppermost formation of the Edmonton Group, although some early workers included it in the overlying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lance Formation
The Lance (Creek) Formation is a division of Late Cretaceous (dating to about 69–66 Ma) rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas. The Lance Formation is Late Maastrichtian in age (Lancian NALMA, land mammal age), and shares much fauna with the Hell Creek Formation of Montana and North Dakota, the Frenchman Formation of southwest Saskatchewan, and the lower part of the Scollard Formation of Alberta. The Lance Formation occurs above the ''Baculites clinolobatus'' ammonite marine zone in Wyoming, the top of which has been dated to about 69 million years ago, and extends to the K-Pg boundary, 66 million years ago. However, the characteristic land vertebrate fauna of the Lancian age (which take its name from this formation) is only found in the upper strata of the Lance, roughly corresponding to the thinner equivalent formations such as the H ... [...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 (stratigraphy), 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 West ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intraspecific Competition
Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. This leads to a reduction in fitness for both individuals, but the more fit individual survives and is able to reproduce. By contrast, interspecific competition occurs when members of different species compete for a shared resource. Members of the same species have rather similar requirements for resources, whereas different species have a smaller contested resource overlap, resulting in intraspecific competition generally being a stronger force than interspecific competition. Individuals can compete for food, water, space, light, mates, or any other resource which is required for survival or reproduction. The resource must be limited for competition to occur; if every member of the species can obtain a sufficient amount of every resource then individuals do not compete and the population grows exponentially. Prolonged exponential growth is rar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
