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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] |
Alvarezsauridae
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 it. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratonykus
''Ceratonykus'' (meaning "horned claw") is a monospecific genus of alvarezsaurid dinosaur from Mongolia that lived during the Late Cretaceous (late Campanian stage, 72.1 Ma) in what is now the Barun Goyot Formation. The type and only species, ''Ceratonykus oculatus'', is known from a fragmentary skeleton, including an incomplete skull, of an adult individual. It was named and described in 2009 by Vladimir Alifanov and Rinchen Barsbold. Its describers questioned the traditional placement of alvarezsaurs in Theropoda, instead suggesting they were ornithischians, but this has not been accepted since. ''Ceratonykus'' has an estimated length of 75 centimetres (2.5 feet) and weight of 760 grams (1.68 lbs). It has been considered as a possible junior synonym of '' Parvicursor''. Discovery and naming In 2003, a partial skeleton of an alvarezsaurid was discovered in the Barun Goyot Formation of the Khermiin Tsav locality, Mongolia by the Paleontological Center of the Mongolian Academy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvicursorinae
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 it. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patagonykus
''Patagonykus'' (meaning "Patagonian claw") is a genus of theropod dinosaur from the Upper Cretaceous of Argentina. This alvarezsauroid was discovered in exposures of the Portezuelo Formation (Turonian-Coniacian) of the Rio Neuquén Subgroup in the Neuquén Basin, Neuquen Province of Patagonia, Argentina. The holotype consists of an incomplete but well-preserved skeleton, lacking a skull, but including many vertebrae, the coracoids, a partial forelimb, pelvic girdle, and hindlimbs. ''Patagonykus'' has been classed with the Alvarezsauridae, a family which includes such taxa as the Mongolian ''Mononykus'' and the Argentinian '' Alvarezsaurus''. In 2010 Gregory S. Paul estimated its length at 1 meter (3.3 ft) and its weight at 3.5 kg (7.7 lbs). Classification Agnolin ''et al.'' (2012) originally placed ''Patagonykus'' within Alvarezsauridae, within the clade Patagonykinae as sister taxon to ''Bonapartenykus''. Makovicky, Apesteguía and Gianechini (2012) found it to be in a polyto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bonapartenykus
''Bonapartenykus'' (meaning " José F. Bonaparte's claw") is a monospecific genus of alvarezsauroid dinosaur from Argentina that lived during the Late Cretaceous (Campanian-Maastrichtian) in what is now the upper Allen Formation of the Río Negro Province. The type and only species, ''Bonapartenykus ultimus'', is known from a nearly articulated but partial skeleton that was found in close association to two incomplete eggs and several clusters of eggshells belonging to the oogenus ''Arriagadoolithus''. ''Bonapartenykus'' was named in 2012 by Federico L. Agnolin, Jaime E. Powell, Fernando E. Novas and Martin Kundrát. ''Bonapartenykus'' has an estimated length of and weight of , making it the largest member of the clade Alvarezsauroidea. Discovery and Naming A partial skeleton of a theropod with eggs was collected in a surface of approximately 30 m2 in fluvial sandstones of the upper Allen Formation in northwestern Patagonia, Argentina. The locality has also produced specimen ... [...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. ''Albe ... [...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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kol Ghuva
''Kol'' (from the Mongolian хөл/''köl'', meaning "foot") is an extinct genus of coelurosaurian theropod dinosaur from the Late Cretaceous of Mongolia. The type and only species is ''Kol ghuva'' (from the Mongolian гува/''ghuv-a'', meaning "beautiful"). The type specimen was excavated from the Ukhaa Tolgod locality of the Djadochta Formation, dating to about 75 million years ago. It is believed to have been about twice the size of the contemporary ''Shuvuuia''. However, unlike ''Shuvuuia'', which is known from many well preserved specimens, and although Ukhaa Tolgod has been thoroughly explored, ''Kol'' is known only from one complete foot, suggesting that it must have been relatively rare in that ecosystem. Because of the incomplete nature of the type specimen (catalog number IGM 100/2011), the exact relationship of ''Kol'' to other coelurosaurs has been difficult to determine. However, ''Kol'' shows an extreme arctometatarsalian condition of the foot bones, in which t ... [...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 '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alvarezsaurus
''Alvarezsaurus'' (; "Alvarez's lizard") is a genus of alvarezsaurid dinosaur from the Late Cretaceous, living in Argentina approximately 86 - 83 million years ago. It was a small dinosaur, measuring long and weighing approximately . It was found in the Bajo de la Carpa Formation and was named by paleontologist José Bonaparte in 1991 after the historian Don Gregorio Alvarez. The type species is ''A. calvoi''. Description ''Alvarezsaurus'' was a bipedal theropod. Like other lightweight theropods, it had a long tail, and its leg structure suggests that it was a fast runner. The most proximal elements of ''Alvarezsaurus'' caudal vertebrae exhibited ventrally sharp centra and the transerve processes of these vertebrae were sub-triangular and laterodistally directed, features seen in other alvarezsaurids like ''Shuvuuia''. Spinal processes were entirely absent or poorly developed, and each caudal vertebra supported short prezygapophyses. The scapula was visibly curved and proportio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achillesaurus
''Achillesaurus'' is a genus of alvarezsaurid theropod dinosaur from the Santonian-age Upper Cretaceous Bajo de la Carpa Formation of Rio Negro, Argentina. It was named in reference to Achilles' heel, because diagnostic features are found there for these animals. The genus was a relatively large, basal alvarezsaurid, and a contemporary of ''Alvarezsaurus''. ''Achillesaurus'' is based on MACN-PV-RN 1116, a partial skeleton including a sacral vertebra, four tail vertebrae, part of the left thighbone, shin and foot, and the left ilium. Agustín Martinelli and Ezequiel Vera, who described the specimen, performed a phylogenetic analysis and found their new genus to be an alvarezsaurid with an unresolved relationship to ''Alvarezsaurus'' and more derived Derive may refer to: * Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
