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Canadaga
''Canadaga'' (meaning "Canadian bird") is a flightless bird genus from the Late Cretaceous. The single known species is ''Canadaga arctica''. It lived in the shallow seas around what today is Bylot and Devon Islands in Nunavut, Canada. Its fossils were found in rocks dated to the Campanian to mid-Maastrichtian age, about 67 million years ago. It was found in the Kanguk Formation It was a member of the Hesperornithes, flightless toothed seabirds of the Cretaceous. Among these, it belonged to the Hesperornithidae, along with '' Hesperornis'', the well-known namesake genus. Description ''C. arctica'' is one of the largest known members of the Hesperornithes, reaching a length of . It also represents one of the last known members of the lineage. Unlike its relatives which are mainly known from subtropical or tropical waters, this species seems to have ranged in temperate or even subarctic areas. The species is described from 3 associated cervical vertebrae, one caudal vertebra a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornithidae
Hesperornithes is an extinct and highly specialized group of aquatic avialans closely related to the ancestors of modern birds. They inhabited both marine and freshwater habitats in the Northern Hemisphere, and include genera such as '' Hesperornis'', '' Parahesperornis'', '' Baptornis'', '' Enaliornis'', and '' Potamornis'', all strong-swimming, predatory divers. Many of the species most specialized for swimming were completely flightless. The largest known hesperornithean, '' Canadaga arctica'', may have reached a maximum adult length of . Hesperornitheans were the only Mesozoic avialans known to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with enantiornitheans and all other non-avian dinosaurs. Anatomy and ecology Most of what is known about this group rests on analyses of single species, as few provide sufficiently complete fossils for analysis. Although some of the smaller and more basal species, like those belonging to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornithes
Hesperornithes is an extinct and highly specialized group of aquatic Avialae, avialans closely related to the ancestors of modern birds. They inhabited both marine and freshwater habitats in the Northern Hemisphere, and include genus, genera such as ''Hesperornis'', ''Parahesperornis'', ''Baptornis'', ''Enaliornis'', and ''Potamornis'', all strong-swimming, predatory divers. Many of the species most specialized for swimming were completely flightless. The largest known hesperornithean, ''Canadaga arctica'', may have reached a maximum adult length of . Hesperornitheans were the only Mesozoic avialans known to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with Enantiornithes, enantiornitheans and all other non-avian dinosaurs. Anatomy and ecology Most of what is known about this group rests on analyses of single species, as few provide sufficiently complete fossils for analysis. Although some of the smaller and more basal species, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornis
''Hesperornis'' (meaning "western bird") is a genus of cormorant-like Ornithuran that spanned throughout the Campanian age, and possibly even up to the early Maastrichtian age, of the Late Cretaceous period. One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an early find in the history of avian paleontology. Locations for ''Hesperornis'' fossils include the Late Cretaceous marine limestones from Kansas and the marine shales from Canada. Nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia. Description ''Hesperornis'' was a large bird, measuring about long and weighing around . It had virtually no wings, and swam with its powerful hind legs. Studies on the feet initially indicated that ''Hesperornis'' and kin had lobed toes similar to modern-day grebes, as opposed to webbed toes as seen in most aquatic birds such as loons. More recent work looking at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kanguk Formation
The Kanguk Formation is a geological formation in the Northwest Territories and Nunavut, Canada whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. . It was first described in the Kanguk Peninsula of the Axel Heiberg Island, along the shore of the Stand Fiord by Souther in 1963. The formation occurs throughout the Sverdrup Basin and the southern Queen Elizabeth Islands. Lithology The Kanguk Formation is composed of dark shale and siltstone with interbeds of sandstone, bentonite and tuff. Thicker sandstone and conglomerate beds occur in the western reaches in Eglinton Island. Fossil content The Kanguk Formation preserves an extensive record of shelf assembla ... [...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] |
Maastrichtian
The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (stratigraphy), Series, the Cretaceous geologic period, Period or system (stratigraphy), System, and of the Mesozoic geologic era, 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). It is named after the city of Maastricht, the capital and largest city of the Limburg (Netherlands), Limburg province in the Netherlands. The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary period, Tertiary extinction event) occurred at the end of this age. In this extinction event, mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Genera
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femoral head, top of the femur fits into a socket in the pelvis called the hip joint, and the bottom of the femur connects to the shinbone (tibia) and kneecap (patella) to form the knee. In humans the femur is the largest and thickest bone in the body. Structure The femur is the only bone in the upper Human leg, leg. The two femurs converge Anatomical terms of location, medially toward the knees, where they articulate with the Anatomical terms of location, proximal ends of the tibiae. The angle at which the femora converge is an important factor in determining the femoral-tibial angle. In females, thicker pelvic bones cause the femora to converge more than in males. In the condition genu valgum, ''genu valgum'' (knock knee), the femurs conve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subarctic
The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of hemiboreal regions and covering much of Alaska, Canada, Iceland, the north of Fennoscandia, Northwestern Russia, Siberia, and the Cairngorms. Generally, subarctic regions fall between 50°N and 70°N latitude, depending on local climates. Precipitation is usually low, and vegetation is characteristic of the taiga. Daylight at these latitudes is quite extreme between summer and winter due to its high latitude. Near the summer solstice for instance, subarctic regions can experience an all-night period of either civil, nautical, or astronomical twilight (or in the northern reaches full daylight), since the sun never dips more than 18 degrees below the horizon. Noctilucent clouds are best observed within this range of latitude. Climate and soils Subarctic temperatures are above for at least one and at most three months of the year. Precipitation tends to be low due to ... [...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 outcrops 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flightless Bird
Flightless birds are birds that cannot Bird flight, fly, as they have, through evolution, lost the ability to. There are over 60 extant species, including the well-known ratites (ostriches, emus, cassowary, cassowaries, Rhea (bird), rheas, and Kiwi (bird), kiwis) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird in general, is the common ostrich (2.7 m, 156 kg). Many domesticated birds, such as the domestic chicken and domestic duck, have lost the ability to fly for extended periods, although their ancestral species, the red junglefowl and mallard, respectively, are capable of extended flight. A few particularly bred birds, such as the Broad Breasted White turkey, have become totally flightless as a result of selective breeding; the birds were bred to grow massive breast meat that weighs too much for the bird's wings ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of countries and dependencies by area, second-largest country by total area, with the List of countries by length of coastline, world's longest coastline. Its Canada–United States border, border with the United States is the world's longest international land border. The country is characterized by a wide range of both Temperature in Canada, meteorologic and Geography of Canada, geological regions. With Population of Canada, a population of over 41million people, it has widely varying population densities, with the majority residing in List of the largest population centres in Canada, urban areas and large areas of the country being sparsely populated. Canada's capital is Ottawa and List of census metropolitan areas and agglomerations in Canada, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
