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Lavocatavis
''Lavocatavis'' is an extinct genus of phorusrhacoid or "terror bird" from the Eocene of Algeria. A fossilized femur was described from the Glib Zegdou Formation in 2011 and is the only known specimen of ''Lavocatavis''. The species was designated ''L. africana''. Discovery and naming The holotype of ''Lavocatavis'', UM HGL 51-55, consists of an almost complete right femur. It is reasonably well preserved in the middle, but fragmentary at both ends. It originates from layer HGL 51 of the Glib Zegdou Formation of Algeria. The generic epithet (meaning "Lavocat's bird") was named in honor of René Lavocat, the person who first reported the earth layer of the holotype. Paleobiogeography The oldest phorusrhacoids are from South America and Antarctica, suggesting that the ancestors of ''Lavocatavis'' migrated into Africa from the west. During the Eocene, the Atlantic Ocean separated South America from Africa by at least , ruling out a land migration. For a flightless terrestrial bir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phorusrhacidae
Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal range covers from 62 to 0.1 million years ( Ma) ago. They ranged in height from . Their closest modern-day relatives are believed to be the seriemas. ''Titanis walleri'', one of the larger species, is known from Texas and Florida in North America. This makes the phorusrhacids the only known large South American predator to migrate north in the Great American Interchange that followed the formation of the Isthmus of Panama land bridge (the main pulse of the interchange began about 2.6 Ma ago; ''Titanis'' at 5 Ma was an early northward migrant). It was once believed that ''T. walleri'' became extinct in North America around the time of the arrival of humans, but subsequent datings of ''Titanis'' fossils provided no evidence for their surv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phorusrhacoid
Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal range covers from 62 to 0.1 million years ( Ma) ago. They ranged in height from . Their closest modern-day relatives are believed to be the seriemas. ''Titanis walleri'', one of the larger species, is known from Texas and Florida in North America. This makes the phorusrhacids the only known large South American predator to migrate north in the Great American Interchange that followed the formation of the Isthmus of Panama land bridge (the main pulse of the interchange began about 2.6 Ma ago; ''Titanis'' at 5 Ma was an early northward migrant). It was once believed that ''T. walleri'' became extinct in North America around the time of the arrival of humans, but subsequent datings of ''Titanis'' fossils provided no evidence for their survi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio Grande Rise
The Rio Grande Rise, also called the Rio Grande Elevation or Bromley Plateau, is an aseismic ocean ridge in the southern Atlantic Ocean off the coast of Brazil. Together with the Walvis Ridge off Africa, the Rio Grande Rise forms a V-shaped structure of mirrored hotspot tracks or seamount chains across the northern South Atlantic. In 2013, Brazilian scientists announced that they found granite boulders on the Rio Grande Rise and speculated that it could be the remains of a submerged continent, which they called the "Brazilian Atlantis". Other researchers, however, noted that such boulders can end-up on the ocean floor by less speculative means. Geology The Rio Grande Rise separates the Santos and Pelotas Basins and is composed of western and eastern areas, which have different geological backgrounds. The western area has numerous guyots and seamounts and a basement dated to . The eastern area is covered by fracture zones and may represent an abandoned spreading centre. In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Island Hopping
Leapfrogging, also known as island hopping, was a military strategy employed by the Allies in the Pacific War against the Empire of Japan during World War II. The key idea is to bypass heavily fortified enemy islands instead of trying to capture every island in sequence en route to a final target. The reasoning is that those islands can simply be cut off from their supply chains (leading to their eventual capitulation) rather than needing to be overwhelmed by superior force, thus speeding up progress and reducing losses of troops and materiel. Background By the late 19th century, the U.S. had several interests in the western Pacific to defend; namely, access to the Chinese market, and its colonies – the Philippines and Guam – which the U.S. had gained as a result of the Spanish–American War (1898). After Japan's victories in the Sino-Japanese War (1894–95) and the Russo-Japanese War of 1904, the U.S. began to regard Japan as a potential threat to its interests in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 2011
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] |
Eocene Birds
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the ... [...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] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walvis Ridge
The Walvis Ridge (''walvis'' means whale in Dutch and Afrikaans) is an aseismic ocean ridge in the southern Atlantic Ocean. More than in length, it extends from the Mid-Atlantic Ridge, near Tristan da Cunha and the Gough Islands, to the African coast (at 18°S in northern Namibia). The Walvis Ridge is one of few examples of a hotspot seamount chain that links a flood basalt province to an active hotspot. It is also considered one of the most important hotspot tracks because the Tristan Hotspot is one of few primary or deep mantle hotspots. Geology Apart from the Mid-Atlantic Ridge, the Walvis Ridge and the Rio Grande Rise are the most distinctive feature of the South Atlantic sea floor. They originated from hotspot volcanism and together they form a mirrored symmetry across the Mid-Atlantic Ridge, with the Tristan Hotspot at its centre. Two of the distinct sections in the Walvis Ridge have similar mirrored regions in the Rio Grande Rise; for example, the eastern section of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2011 In Paleontology
Protozoa New taxa Plants Ferns and fern allies Gymnosperms Gymnosperm research *An amplified whole plant reconstruction of the Ypresian Princeton chert pine '' Pinus arnoldii'', expanding the diagnosis to include ''P. similkameenensis'' (Miller, 1973 Events January * January 1 - The United Kingdom, the Republic of Ireland and Denmark enter the European Economic Community, which later becomes the European Union. * January 15 – Vietnam War: Citing progress in peace negotiations, U.S. ...) foliage and wood plus unnamed pollens cones found in attachment to the ''P. arnoldii'' ovulate cones is published by Klymiuk, Stockey, & Rothwell. Angiosperms Nematoda Lobopods Vetulicolians Molluscs Arthropods Fishes Amphibians Newly named lepospondyls Newly named temnospondyls Newly named lissamphibians Basal reptiles Newly named captorhinids Newly named basal diapsids Newly named ichthyosaurs Lepidosauromorphs Newly named saurosphargids New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany, an isotype is a duplicate of the holotype, where holotype and isotypes are often pieces from the same individual plant or samples from the same gathering. A holotype is not necessarily "typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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