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Asiahesperornis
''Asiahesperornis'' is a prehistoric foot-propelled diving toothed flightless bird genus from the Late Cretaceous. The single known species is ''Asiahesperornis bazhanovi''. It lived in what today is Kazakhstan, at its time the shores of the shallow Turgai Sea. It was a member of the Hesperornithes, flightless toothed seabirds of the Cretaceous. Its exact relationships are not completely resolved, but it probably belongs into the Hesperornithidae just like ''Hesperornis'', well known from the Western Interior Seaway that covered most of the US Midwest in the Mesozoic. Its name is derived from its findings in Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area .... References Bird genera Extinct flightless birds Fossil taxa described in 1991 Hesperornitheans Late Cretaceo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornitheans
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 to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with enantiornitheans and all other non-avian dinosaurs, and many other diverse plant and animal groups. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornithes
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 to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with enantiornitheans and all other non-avian dinosaurs, and many other diverse plant and animal groups. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flightless Bird
Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species, including the well known ratites (ostriches, emu, cassowaries, rheas, and kiwi) 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, is the 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 to support in flight. Flightlessness has evolved in many different birds independently, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornis
''Hesperornis'' (meaning "western bird") is a genus of cormorant-like bird that spanned the first half of the Campanian age of the Late Cretaceous period (83.5–78 mya). 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, reaching up to in length. 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 morphometrics of the feet in hesperornithiformes and mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 1991
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Flightless Birds
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Genera
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have 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 loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. Bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area of , about 30% of Earth's total land area and 8.7% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East–West cultural, linguistic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot Greenhouse and icehouse earth, greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since Cambrian explosion, complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, Pterosaur, pterosaurs, Mosasaur, mosasaurs, and Plesiosaur, plesiosaurs. The Mesozoic was a time of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midwest
The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four Census Bureau Region, census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. It was officially named the North Central Region by the Census Bureau until 1984. It is between the Northeastern United States and the Western United States, with Canada to the north and the Southern United States to the south. The Census Bureau's definition consists of 12 states in the north central United States: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin. The region generally lies on the broad Interior Plain between the states occupying the Appalachian Mountains, Appalachian Mountain range and the states occupying the Rocky Mountains, Rocky Mountain range. Major rivers in the region include, from east to west, the Ohio River, the Upper Mis ... [...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] |
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