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Dromaeosaurus Minutus
Alvarezsauridae is a family of small, long-legged dinosaurs. Although originally thought to represent the earliest known flightless birds, they are now thought to be an early diverging branch of maniraptoran theropods. Alvarezsaurids were highly specialized. They had tiny but stout forelimbs, with compact, bird-like hands. Their skeletons suggest that they had massive breast and arm muscles, possibly adapted for digging or tearing. They had long, tube-shaped snouts filled with tiny teeth. They have been interpreted as myrmecophagous, adapted to prey on colonial insects such as termites, with the short arms acting as effective digging instruments to break into nests. '' Alvarezsaurus'', the type genus of the family, was named for the historian Gregorio Álvarez. History of study Bonaparte (1991) described the first alvarezsaurid, ''Alvarezsaurus calvoi'', from an incomplete skeleton found in Patagonia, Argentina. Bonaparte also named a family, Alvarezsauridae, to contain ... [...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] |
Trierarchuncus
''Trierarchuncus'' (meaning "captain hook," after its single-clawed hands) is a monotypic genus of alvarezsaurid theropod which includes a single species, ''Trierarchuncus prairiensis'', which is known from fossils found in deposits of the Hell Creek Formation in Montana. It is the youngest known alvarezsaurid and one of the last non-avian dinosaurs, going extinct during the Cretaceous–Paleogene extinction event, which occurred approximately 66 million years ago. Discovery and naming The first remains ware discovered in Montana in 1980 and it was informally known as the "Hell Creek alvarezsaur".Hutchinson and Chiappe, 1998. The first known alvarezsaurid (Theropoda: Aves) from North America. ''Journal of Vertebrate Paleontology''. 18(3), 447–450. The then unnamed species was not mentioned again until it was mentioned briefly in the 2018 Society of Vertebrate Paleontology abstract book. The species and genus were scientifically described by Denver Fowler and colleagues in 2020 ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. '' Ornitholestes'' and the Alvarezsauroidea are also often included. Together with the next closest sister group, the Ornithomimosauria, Maniraptora comprises the more inclusive clade Maniraptoriformes. Maniraptorans first appear in the fossil record during the Jurassic Period (see '' Eshanosaurus''), and survive today as living birds. Description Maniraptorans are characterized by long arms and three-fingered hands (though reduced or fused in some lineages), as well as a "half-moon shaped" (semi-lunate) bone in the wrist (carpus). In 2004, Tom Holtz and Halszka Osmólska pointed out six other maniraptoran characters relating to specific details of the skeleton. Unlike most other saurischian dinosaurs, which h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
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. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family ( la, familia, plural ') is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyril Walker (ornithologist)
Cyril Alexander Walker (8 February 1939 – 6 May 2009) was a British palaeontologist, curator of fossil birds in the Natural History Museum. He was also interested in fossil turtles. book, '' Smithsonian Handbook of Fossils''. He has also contributed to many other books, including ''Garden Birds'', ''Field Guide to British Birds'', ''Birds of the World'', ''Nature Notebooks'', and others. An unidentified moa bone of unknown origin and locality, donated by Dr. C. Walker to ornithologist Zlatozar Boev Zlatozar Boev (born 20 October 1955) is a Bulgarian ornithologist, paleontologist, and zoologist. He has published 345 papers and other material, in Bulgarian, English, French, and Russian. He has classified 36 taxa. Boev is a part of the Nationa ... in 1986, was later identified as the little bush moa (''Anomalopteryx didiformis'').1. Boev, Z. 2018. A specimen of little bush moa Anomalopteryx didiformis (Owen, 1844), Emeidae Bonaparte, 1854 from the National Museum of Natural Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colin Harrison (ornithologist)
Colin James Oliver Harrison (18 August 1926 – 17 November 2003) was an English ornithologist. Harrison was born in London. He got a scholarship to grammar school, and then worked as a librarian and a teacher. He had been interested in birds since childhood, and joined an expedition to study autumn migration in Norway. He became a professional ornithologist at the age of 34 and became responsible for the care of the national collection of birds' nests and eggs in the Bird Room at the Natural History Museum at Tring, Hertfordshire. In 1966 he led the fourth of the series of Harold Hall Australian ornithological collecting expeditions. Harrison later became interested in biogeography and the museum's avian paleontological collection, on which he published a number of articles with Cyril Walker. He studied and published on different aspects of bird behaviour, on plumage patterns, and on the bone structure of modern and fossil birds. He identified ''Eostrix ''Eostrix'' is a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shuvuuia
''Shuvuuia'' is a genus of bird-like theropod dinosaur from the late Cretaceous period of Mongolia. It is a member of the family Alvarezsauridae, small coelurosaurian dinosaurs which are characterized by short but powerful forelimbs specialized for digging. The type (and only known) species is ''Shuvuuia deserti'', or "desert bird".Chiappe, L.M., Norell, M. A., and Clark, J. M. (1998). "The skull of a relative of the stem-group bird ''Mononykus''." ''Nature'', 392(6673): 275-278. The name ''Shuvuuia'' is derived from the Mongolian word ''shuvuu'' (шувуу) meaning "bird". Description ''Shuvuuia'' was a small and lightly built animal. At in length and in body mass, it is one of the smallest known non-avian dinosaurs. The skull is lightly built with long and slender jaws and minute teeth. ''Shuvuuia'' is unique among non-avian theropods in the skull's ability to perform prokinesis, that is, it could flex its upper jaw independently of its braincase. The hindlimbs of ''Shuvu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linhenykus
''Linhenykus'' is an extinct genus of alvarezsaurid theropod dinosaur from the Late Cretaceous of Inner Mongolia, China. It is the most basal known member of the Parvicursorinae. The genus gets its name from Linhe, a city near the site where the fossil was first found and Greek ''nykus'', "claw". The specific name is derived from Greek ''monos'', "single", and ''daktylos'', "finger", a reference to the fact that it is the only known non-avian dinosaur to have had but a single digit. Description ''Linhenykus'' was a small dinosaur, measuring long and weighing . Its femur length is . Alvarezsauroids are known for their short forelimbs, each with a single greatly enlarged second digit. Although alvarezsaurids were once thought to have only a single digit on each forelimb, more recent evidence has shown that most species have reduced third and fourth digits. ''Linhenykus'' is the first known alvarezsaurid to have only a single, second digit. Although a reduced third metacarpal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albertonykus
''Albertonykus'' (meaning "Alberta claw") is an alvarezsaurid dinosaur from the Maastrichtian-age (Upper Cretaceous) rocks of the Horseshoe Canyon Formation of Alberta, Canada. It is known from forelimb and hindlimb remains from multiple individuals. All but two of the specimens come from a bonebed dominated by ''Albertosaurus'', located at the top of Unit 4 of the Horseshoe Canyon Formation,Larson, D. W., Brinkman, D. B., & Bell, P. R. (2010). Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebed This article is one of a series of papers published in this Special Issue on the theme Albertosaurus. Canadian Journal of Earth Sciences, 47(9), 1159-1181. dating to ~68.5 million years ago. ''Albertonykus'' is interpreted as having fed on wood-nesting termites because the forelimbs appear specialized for digging, but are too short for burrowing. ''Alber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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