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Parahesperornis Alexi
''Parahesperornis'' is a genus of prehistoric flightless birds from the Late Cretaceous. Its range in space and time may have been extensive, but its remains are rather few and far between, at least compared with its contemporary relatives in ''Hesperornis''. Remains are known from central North America, namely the former shallows of the Western Interior Seaway in Kansas. Found only in the upper Niobrara Chalk, these are from around the Coniacian-Santonian boundary, 85-82 million years ago (mya). ''Parahesperornis alexi'' (Martin, 1984) was long lumped with specimen YPM 1478, described initially as ''Hesperornis gracilis'' and later moved to the monotypic genus ''Hargeria'' (Lucas, 1903). It then turned out that this genus' description actually referred to specimen KUVP 2287, which eventually became the holotype of ''P. alexi''. Nonetheless, the taxon description of ''Hargeria'' was about ''"Hesperornis" gracilis'' exclusively, and thus despite the misidentification it applies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger 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, Australia and Ant ... [...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] |
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] |
UC Davis
The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The institution was first founded as an agricultural branch of the system in 1905 and became the seventh campus of the University of California in 1959. The university is classified among "R1: Doctoral Universities – Very high research activity". The UC Davis faculty includes 23 members of the National Academy of Sciences, 30 members of the American Academy of Arts and Sciences, 17 members of the American Law Institute, 14 members of the Institute of Medicine, and 14 members of the National Academy of Engineering. Among other honors that university faculty, alumni, and researchers have won are two Nobel Prizes, one Fields Medal, a Presidential Medal of Freedom, three Pulitzer Prizes, three MacArthur Fellowships, and a National Medal of Science. Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceans Of Kansas Paleontology
''Oceans of Kansas'' is a book by Michael J. Everhart, Adjunct Curator of Paleontology at the Sternberg Museum of Natural History and past President of the Kansas Academy of Science. It was published in 2005 by Indiana University Press. It has an award-winning, concomitant website entitled Oceans of Kansas Paleontology. A revised, updated, and expanded edition was published in 2017. It is part of the life of the past series. Summary In ''Oceans of Kansas'' Everhart discusses the state of the land during the Late Cretaceous and earlier, when the area was covered with the marine waters of the Western Interior Seaway, particularly focusing on the record of the Niobrara Cycle of the Seaway as exposed in central Northwestern Kansas (e.g., Trego and Gove Counties). The geologic record shows that ancient lifeforms such as marine reptiles, pteranodons, and toothed birds inhabited the general area both in and out of the water. Everhart also covers the discovery of the fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kansas Geological Survey
The Kansas Geological Survey (KGS), a research and service division of the University of Kansas, is charged by statute with studying and providing information on the geologic resources of Kansas. The KGS has no regulatory authority and does not take positions on natural resource issues. Research at the KGS focuses primarily on energy, water, and the environment and addresses natural resource challenges facing the state of Kansas. The KGS also generates new information about the state's geology and develops tools and techniques for studying the state's surface and subsurface through its geophysics and mapping programs. Primary users of this information include local, State, and Federal agencies; oil and gas exploration companies; engineering companies and geotechnical consultants dealing with construction, environmental, and geologic hazard issues; educators; and private citizens wanting to learn more about the state's geology and resources. The KGS is located in Lawrence on the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornithiformes
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] |
Tibiotarsus
The tibiotarsus is the large bone between the femur and the tarsometatarsus in the leg of a bird. It is the fusion of the proximal part of the tarsus with the tibia. A similar structure also occurred in the Mesozoic Heterodontosauridae. These small ornithischian dinosaurs were unrelated to birds and the similarity of their foot bones is best explained by convergent evolution. See also *Bird anatomy References * Proctor, Nobel S. ''Manual of Ornithology: Avian Structure and Function''. Yale University Press Yale University Press is the university press of Yale University. It was founded in 1908 by George Parmly Day, and became an official department of Yale University in 1961, but it remains financially and operationally autonomous. , Yale Universi .... (1993) Bird anatomy {{ornithology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mongolia
Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, making it the world's most sparsely populated sovereign nation. Mongolia is the world's largest landlocked country that does not border a closed sea, and much of its area is covered by grassy steppe, with mountains to the north and west and the Gobi Desert to the south. Ulaanbaatar, the capital and largest city, is home to roughly half of the country's population. The territory of modern-day Mongolia has been ruled by various nomadic empires, including the Xiongnu, the Xianbei, the Rouran, the First Turkic Khaganate, and others. In 1206, Genghis Khan founded the Mongol Empire, which became the largest contiguous land empire in history. His grandson Kublai Khan conquered China proper and established the Yuan dynasty. After the co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsagaan Kushu
Tsagaan (Mongolian: цагаан, ''white'', zh, 查干) may refer to: People * Monguor people or ''Tsagaan mongghol'', a Mongol ethnic group in China * Okna Tsahan Zam (born 1957), a Kalmyk throat singer * Chagaan, 13th-century commander of the Mongol Empire Places in Mongolia * Baatsagaan, Bayankhongor * Bayantsagaan, Bayankhongor * Bayantsagaan, Töv * Buutsagaan, Bayankhongor * Erdenetsagaan, Sükhbaatar * Saintsagaan, Dundgovi * Tsagaanchuluut, Zavkhan * Tsagaandelger, Dundgovi * Tsagaankhairkhan, Uvs * Tsagaankhairkhan, Zavkhan * Tsagaan-Ovoo, Dornod * Tsagaan-Uul, Khövsgöl * Tsagaan-Üür, Khövsgöl Others * Tsagaan Sar, the Mongolian New Year festival * ''Tsaagan ''Tsaagan'' (meaning "white") is a genus of dromaeosaurid dinosaur from the Djadokhta Formation of the Late Cretaceous of Mongolia. Discovery and naming The holotype of ''Tsaagan'' was discovered in 1996 and first identified as a specimen of '' ...'', the dinosaur ''Tsaagan mangas'' (te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic 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). The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) occurred at the end of this age. In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about wide colliding with Earth, ending the Cretaceous. Stratigraphic definitions Definition The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the Chalk Group c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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