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Anserimorphs Size Comparison
The Odontoanserae is a proposed clade that includes the family Pelagornithidae (pseudo-toothed birds) and the clade Anserimorphae (the order Anseriformes and their stem-relatives). The placement of the pseudo-toothed birds in the evolutionary tree of birds has been problematic, with some supporting the placement of them near the orders Procellariformes and Pelecaniformes based on features in the sternum. In 2005 a cladistic analysis had found support in placing pseudo-toothed birds as the sister group to waterfowl. Evidence for this comes from shared characteristics in the skull such as lack of a crest on the underside of the palatine bone and two condyles on the mandibular process of the quadrate bone, with the middle condyle beakwards of the side condyle. In addition to that, both groups have similar features in their pelvic and pectoral regions. Furthermore, a 2013 study on the growth pattern and structure of the pseudoteeth in ''Pelagornis mauretanicus'' shows more support of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagornis
''Pelagornis'' is an extinct genus of prehistoric pseudotooth birds, a group of extinct seabirds. Species span from the Oligocene to the Early Pleistocene. Members of ''Pelagornis'' represent among the largest pseudotooth birds, with one species. ''P. sandersi'', having the widest wingspan of any bird known. Taxonomy Four species have been formally described, but several other named taxa of pseudotooth birds might belong in ''Pelagornis'' too. The type species ''Pelagornis miocaenus'' is known from Aquitanian age, Aquitanian (Early Miocene) sediments – formerly believed to be of Middle Miocene age – of Armagnac (region), Armagnac (France). The original specimen on which ''P. miocaenus'' was founded was a left humerus almost the size of a human arm. The scientific name – "the most unimaginative name ever applied to a fossil" in the view of Storrs L. Olson – does in no way refer to the bird's startling and at that time unprecedented proportions, and merely means "Miocene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Presbyornis Enhancement
''Presbyornis'' is an extinct genus of presbyornithid bird from North America during the Paleogene period, between the Late Paleocene and Early Eocene. History of discovery The fossil record of ''P. pervetus'' includes many complete skeletons from Green River Formation sites (Early Eocene), suggesting that the birds nested in colonies and that they possibly died due to volcanism or botulism, the latter of which is similar to many colony-nesting waterfowl or shorebirds today. Fossils identified as ''P.'' cf. ''pervetus'' have been discovered from the Margaret Formation of Ellesmere Island, where the remains of ''Gastornis'' sp. have also been found. ''P. recurvirostra'' is known from a partial wing ( KUVP 10105) found in the Colton Formation, from the Late Paleocene to Early Eocene sediments of the Wasatch Plateau near Ephraim, Utah. ''P. isoni'', much larger than ''P. pervetus'', is known from the Late Paleocene Aquia Formation in Maryland, based on the partial humerus (USNM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual Climate of Antarctica#Precipitation, precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the Lowest temperature recorded on Earth, lowest measured temperature on Earth, . The coastal regions can reach temperatures over in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact (Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pangalliformes
Pangalliformes is the scientific name of a provisional clade of birds within the group Galloanserae. It is defined as all birds more closely related to chickens than to ducks, and includes all modern chickens, turkeys, pheasants, and megapodes, as well as extinct species that do not fall within the crown group Galliformes. Classification Galliform-like pangalliformes are represented by extinct families from the Paleogene, namely the Gallinuloididae, Paraortygidae and Quercymegapodiidae. In the early Cenozoic, some additional birds may or may not be early Galliformes, though even if they are, it is rather unlikely that these belong to extant families: * †'' Argillipes'' (London Clay Early Eocene of England) * †'' Coturnipes'' (Early Eocene of England, and Virginia, USA?) * †'' Paleophasianus'' (Willwood Early Eocene of Bighorn County, USA) * †'' Percolinus'' (London Clay Early Eocenee of England) * †''"Palaeorallus" alienus'' (middle Oligocene of Tatal-Gol, Mongolia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vegaviiformes
Vegaviidae is a proposed extinct family of anseriform birds which lived during the Late Cretaceous and possibly the Paleocene. The monophyly of the family has been questioned by subsequent studies, with the only definitive member ''Vegavis'' known from the Maastrichtian stage of Antarctica, though some fossil genera from other continents have been assigned to this clade. Taxonomic history In 2017, Agnolín and colleagues performed a phylogenetic analysis of various extinct avian genera from the Late Cretaceous of Southern Hemisphere including ''Vegavis''. They found support for those genera making up a family of birds showing specializations to diving, and proposed the family Vegaviidae which is classified as stem-Anseriformes. They also suggested that some fragmentary specimens from the Paleogene of New Zealand, Chile and Antarctica represent indeterminate vegaviids, providing evidence that some families of modern birds crossed the K–Pg boundary unaffected by the extinction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greylag Flipped
The greylag goose (''Anser anser'') is a species of large goose in the waterfowl family Anatidae and the type species of the genus ''Anser (bird), Anser''. It has mottled and barred grey and white plumage and an orange beak and pink legs. A large bird, it measures between in length, with an average weight of . Its distribution is widespread, with birds from the north of its range in Europe and Asia often Bird migration, migrating southwards to spend the winter in warmer places, although many populations are resident, even in the north. It is the ancestor of most breeds of domestic goose, having been domesticated at least as early as 1360 BCE. The genus name and specific epithet are from ''anser'', the Latin for "goose". In the USA, its name has been spelled "graylag". Greylag geese travel to their northerly breeding grounds in spring, nesting on moorlands, in marshes, around lakes and on coastal islands. They normally mate for life and nest on the ground among vegetation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
