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Asteriornis Maastrichtensis
''Asteriornis'' ("Asteria (Titaness), Asteria's bird") is an extinct genus of bird from the Late Cretaceous of Belgium which is known from a single species, ''Asteriornis maastrichtensis''. It was closely related to birds of the extant superorder Galloanserae such as chickens and ducks. Members of the genus were small, long-legged birds (~394 g) that lived near the coastline and co-existed with more "primitive" types of birds such as ''Ichthyornis. Asteriornis'' is one of the oldest-known birds irrefutably belonging to the group Neornithes, which encompasses all modern birds. It possesses characteristics of both galliformes (chicken-like birds) and anseriformes (duck-like birds), indicating its position as a close relative of the last common ancestor for both groups. ''Asteriornis'' may shed light on why Neornithes were the only Dinosaur, dinosaurs to survive the Cretaceous–Paleogene extinction event. Its coexistence with non-neornithean birds such as ''Ichthyornis'' implies that ... [...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] |
Vegavis
''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] |
Chicxulub Impactor
The Chicxulub crater () is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore near the community of Chicxulub, after which it is named. It was formed slightly over 66 million years ago when a large asteroid, about in diameter, struck Earth. The crater is estimated to be in diameter and in depth. It is the second largest confirmed impact structure on Earth, and the only one whose peak ring is intact and directly accessible for scientific research. The crater was discovered by Antonio Camargo and Glen Penfield, geophysicists who had been looking for petroleum in the Yucatán Peninsula during the late 1970s. Penfield was initially unable to obtain evidence that the geological feature was a crater and gave up his search. Later, through contact with Alan R. Hildebrand in 1990, Penfield obtained samples that suggested it was an impact feature. Evidence for the crater's impact origin includes shocked quartz, a gravity anomaly, and tektites ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quail
Quail is a collective name for several genera of mid-sized birds generally placed in the order Galliformes. The collective noun for a group of quail is a flock, covey, or bevy. Old World quail are placed in the family Phasianidae, and New World quail are placed in the family Odontophoridae. The species of buttonquail are named for their superficial resemblance to quail, and form the family Turnicidae in the order Charadriiformes. The king quail, an Old World quail, often is sold in the pet trade, and within this trade is commonly, though mistakenly, referred to as a "button quail". Many of the common larger species are farm-raised for table food or egg consumption, and are hunted on game farms or in the wild, where they may be released to supplement the wild population, or extend into areas outside their natural range. In 2007, 40 million quail were produced in the U.S. New World *Genus ''Callipepla'' **Scaled quail, (commonly called blue quail) ''Callipepla squamata'' **E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
