|
Alvarezsauroidea
Alvarezsauroidea is a group of small maniraptoran dinosaurs. Alvarezsauroidea, Alvarezsauridae, and Alvarezsauria are named for the historian Gregorio Álvarez, not the more familiar physicist Luis Alvarez, or his son geologist Walter Alvarez who jointly proposed that the Cretaceous–Paleogene extinction event was caused by an impact event. The group was first formally proposed by Choiniere and colleagues in 2010, to contain the family Alvarezsauridae and non-alvarezsaurid alvarezsauroids, such as ''Haplocheirus'',Choiniere, J.N., Xu, X., Clark, J.M., Forster, C.A., Guo, Y. and Han, F. (2010). "A basal alvarezsauroid theropod from the early Late Jurassic of Xinjiang, China." ''Science'', 327: 571-574. which is the basalmost of the Alvarezsauroidea (from the Late Jurassic, Asia). The discovery of ''Haplocheirus'' extended the stratigraphic evidence for the group Alvarezsauroidea about 63 million years further in the past. The division of Alvarezsauroidea into the Alvarezsa ... [...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] |
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] |
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] |
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 po ... [...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] |
Shishugounykus
''Shishugounykus'' (meaning "Shishugou claw" after the Shishugou Formation where it was found) is a genus of basal alvarezsaurian dinosaur from the Shishugou Formation from Xinjiang in China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig .... The type and only species is ''Shishugounykus inexpectus''. The specific name refers to the unexpected discovery of another species of alvarezsaur from the Shishugou Formation (other alvarezsaurs from this formation include '' Haplocheirus'' and possibly '' Aorun''). Its affinities to alvarezsaurs has subsequently been questioned. References Alvarezsaurs Oxfordian life Middle Jurassic dinosaurs of Asia Jurassic China Fossils of China Fossil taxa described in 2019 {{theropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined. By the beginning of the Jurassi ... [...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, ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplocheirus
''Haplocheirus'' is a genus of theropod dinosaur. Upon its description, it was considered the oldest alvarezsauroid, predating all other members by about 63 million years. This has subsequently been questioned. A 2019 study considered ''Haplocheirus'' a compsognathid instead of an alvarezsauroid, while a 2022 study considered it to have more similarities with ornithomimosaurs. ''Haplocheirus'' was described in 2010 from a fossil specimen found from the 160-million-year-old Shishugou Formation in the Junggar Basin of northwestern China. The type species is ''H. sollers'', meaning "simple-handed skillful one", referencing its hypothesized behavior of using its three-fingered hands for activities that other alvarezsauroids could not perform, such as catching prey. Description ''Haplocheirus'' had an enlarged thumb claw like alvarezsaurids, but also retained two other functional fingers, unlike alvarezsaurids, where only the thumb was significantly large and clawed. It had long l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tugulusaurus
''Tugulusaurus'' (meaning "Tugulu lizard") is a genus of coelurosaurian theropod dinosaur that belongs to the Alvarezsauroidea. It is known from the Early Cretaceous Tugulu Group in the Urhe area of the People's Republic of China. It was one of the first members of Alvarezsauria ever discovered. Discovery From 1964 dinosaur fossils were excavated in the Junggar Basin of Xinjiang. In 1973 a number of these were described by paleontologist Dong Zhiming, among them the bones of a small theropod which he named ''Tugulusaurus faciles''. The generic name refers to the Tugulu Group. The specific name is derived from Latin ''facilis'', here with the meaning of "easily moving", referring to the agility of the animal as indicated by its "delicate bones". The holotype, IVPP V4025, was found in layers of the Lianmuqin Formation dating from the Barremian–Albian. It consists of a partial skeleton including four partial tail vertebrae, much of the left leg and part of the right, the first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area of , about 30% of Earth's total land area and 8.7% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East–West cultural, linguistic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance ( shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
