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Vegavis Iaai
''Vegavis'' is a genus of extinct bird that lived during the Late Cretaceous (Maastrichtian stage) of Antarctica, some 68 to 66 mya (unit), mya. Among modern birds, most studies show that ''Vegavis'' is most closely related to ducks and goose, geese (Anatidae), but it is not considered to be a direct ancestor of them, although other studies question these results. Taxonomy The holotype specimen of ''Vegavis'' is held by the Museo de La Plata, Argentina. The specimen, cataloged as MLP 93-I-3-1, was found in the López de Bertodano Formation at Cape Lamb on Vega Island, Antarctica, in 1993, but was only described as a new species in 2005 because it consists of the very delicate remains of one bird embedded in a concretion, which had to be meticulously prepared for study. Computed axial tomography, CT scans were utilized to gain a clearer picture of the bone structure without running danger of damaging or destroying the fossil. The genus name, ''Vegavis'', is a combination of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vegavis Restoration
''Vegavis'' is a genus of extinct bird that lived during the Late Cretaceous (Maastrichtian stage) of Antarctica, some 68 to 66 mya. Among modern birds, most studies show that ''Vegavis'' is most closely related to ducks and geese (Anatidae), but it is not considered to be a direct ancestor of them, although other studies question these results. Taxonomy The holotype specimen of ''Vegavis'' is held by the Museo de La Plata, Argentina. The specimen, cataloged as MLP 93-I-3-1, was found in the López de Bertodano Formation at Cape Lamb on Vega Island, Antarctica, in 1993, but was only described as a new species in 2005 because it consists of the very delicate remains of one bird embedded in a concretion, which had to be meticulously prepared for study. CT scans were utilized to gain a clearer picture of the bone structure without running danger of damaging or destroying the fossil. The genus name, ''Vegavis'', is a combination of the name of Vega Island and "avis", the Lati ... [...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] |
López De Bertodano Formation
The Lopez de Bertodano Formation is a geological Formation (geology), formation in the James Ross Island, James Ross archipelago of the Antarctic Peninsula. The strata date from the end of the Late Cretaceous (upper-lower Maastrichtian stage) to the Danian stage of the lower Paleocene, from about 70 to 65.5 million years ago, straddling the Cretaceous-Paleogene boundary. Cretaceous-Paleogene boundary The Cretaceous–Paleogene boundary (K–Pg) crops out on Seymour Island in the upper levels of the Lopez de Bertodano Formation. A small (but significant) iridium anomaly occurs at the boundary on Seymour Island, as at lower latitudes, thought to be fallout from the Chicxulub impactor in the Gulf of Mexico. Directly above the boundary a layer of disarticulated fish fossils occurs, victims of a disturbed ecosystem immediately following the impact event. Multiple reports have described evidence for climatic changes in Antarctica prior to the mass extinction, but the extent to which t ... [...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] |
Acronym
An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as in ''Benelux'' (short for ''Belgium, the Netherlands, and Luxembourg''). They can also be a mixture, as in ''radar'' (''Radio Detection And Ranging''). Acronyms can be pronounced as words, like ''NASA'' and ''UNESCO''; as individual letters, like ''FBI'', ''TNT'', and ''ATM''; or as both letters and words, like '' JPEG'' (pronounced ') and ''IUPAC''. Some are not universally pronounced one way or the other and it depends on the speaker's preference or the context in which it is being used, such as '' SQL'' (either "sequel" or "ess-cue-el"). The broader sense of ''acronym''—the meaning of which includes terms pronounced as letters—is sometimes criticized, but it is the term's original meaning and is in common use. Dictionary and st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleornithology
Paleornithology, also known as avian paleontology, is the scientific study of bird evolution and fossil birds. It is a hybrid of ornithology and paleontology. Paleornithology began with the discovery of ''Archaeopteryx''. The reptilian relationship of birds and their ancestors, the theropod dinosaurs, are important aspects of paleornithological research. Other areas of interest to paleornithologists are the early sea-birds ''Ichthyornis'', ''Hesperornis'', and others. Notable paleornithologists are Storrs L. Olson, Alexander Wetmore, Alan Feduccia, Cécile Mourer-Chauviré, Philip Ashmole, Pierce Brodkorb, Trevor H. Worthy, Zhou Zhonghe, Yevgeny Kurochkin, Bradley C. Livezey, Gareth J. Dyke, Luis M. Chiappe, Gerald Mayr and David Steadman David William Steadman is a paleontologist and ornithologist, and serves as the curator of ornithology at the Florida Museum of Natural History at the University of Florida. His research has concentrated on the evolution, biogeography, conservati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vegaviidae
Vegaviidae is an extinct family of ornithurines, often regarded as stem-anseriforms, which existed during the Late Cretaceous and possibly the Paleocene. Fossils attributed to the family have been found in Canada, Chile, New Zealand, and Antarctica. Previously the genera ''Neogaeornis'' and '' Polarornis'' were classified as stem-loons based on the similarities in the anatomy of the leg structure.Hope, S. (2002). "The Mesozoic radiation of Neornithes." Pp. 339-388 in Chiappe, L.M. and Witmer, L. (eds.), ''Mesozoic Birds: Above the Heads of Dinosaurs''.Carolina Acosta Hospitaleche, Javier N. Gelfo, New Antarctic findings of Upper Cretaceous and lower Eocene loons (Aves: Gaviiformes), Annales de Paléontologie Volume 101, Issue 4, October–December 2015, Pages 315–324 However, there were some criticism to these assertions as the material are from incomplete specimens from Antarctica lacking several important loon characteristics.Feduccia, A. (1999). ''The Origin and Evolution of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australornis
''Australornis'' (Latin: "southern bird") is a genus of extinct seabird discovered in New Zealand. It lived in the Paleocene epoch, 60.5 to 61.6 million years ago (Ma). The type species name originates from ''australis'', Latin for "southern", and ''ornis'', the Greek word for "bird", and ''lovei'' commemorates Leigh Love, an amateur paleontologist who discovered it. ''Australornis'' is one of the oldest flying seabirds. It is also the first non- sphenisciform (penguins and allies) bird fossil discovered from New Zealand for that age. The fossil originates from an era just after the Cretaceous–Paleogene extinction event 66 million years ago. The features of the bird indicate that it does not belong to any of the extant bird families, but to a precursor group or clade which is extinct; hence it is a find of global significance with regard to the evolution of birds. Though the fossil evidence is incomplete to substantiate phylogeny, ''Australornis'' contributes to the emerging ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neogaeornis
''Neogaeornis'' is a controversial prehistoric genus of diving bird. The single known species, ''Neogaeornis wetzeli'', was described from fossils found in the Campanian to Maastrichtian Quiriquina Formation of Chile. It lived about 70-67 million years ago. It remains known from the single tarsometatarsus described in 1929 by Lambrecht, and today housed in the Paläontologisches Institut und Museum in Kiel, Germany.Chiappe (1991) Taxonomy It is controversial because of its uncertain placement. While clearly related to modern birds, ''N. wetzeli'' might not be a particularly close relative, but rather belong to the Baptornithidae, a member of the flightless and toothed Hesperornithes. If this is so, ''Neogaeornis'' is among the very youngest records of this lineage, and the first one from the Southern Hemisphere. However, the Hesperornithiformes are known to have been birds of the open epicontinental and shelf seas which avoided the outer oceans as surrounded South America at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarornis
''Polarornis'' is a genus of prehistoric bird, possibly an anserimorph. It contains a single species ''Polarornis gregorii'', known from incomplete remains of one individual found on Seymour Island, Antarctica, in rocks which are dated to the Late Cretaceous (López de Bertodano Formation, about 66 Ma). The discovery of ''Polarornis gregorii'' was first announced by Sankar Chatterjee in 1989, but he did not describe and officially name the species until 2002.Chatterjee, S. (2002). "The morphology and systematics of ''Polarornis'', a Cretaceous loon (Aves: Gaviidae) from Antarctica." Pp. 125-155 in Zhou and Zhang (eds), ''Proceedings of the 5th Symposium of the Society of Avian Paleontology and Evolution, Beijing, 1–4 June 2000''. Beijing: Science Press. The name ''Polarornis'' had been announced unofficially several years prior to its official publication, in Chatterjee's 1997 book ''The Rise of Birds''.Chatterjee, S. (1997). ''The Rise of Birds''. Baltimore: Johns Hopkins Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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