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Dinosaur Ridge Roadcut I-70
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, Ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful sandstone'')'', t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alwalkeria
''Alwalkeria'' (; "for Alick Walker") is a genus partly based on basal saurischian dinosaur remains from the Late Triassic, living in India. A thighbone found indicates a small bipedal form. It has been seen as a chimera. Etymology This taxon was originally named ''Walkeria maleriensis'' by Sankar Chatterjee in 1987, in honor of British paleontologist Alick Walker. However, since the original generic name was found to be preoccupied by a bryozoan, the name ''Alwalkeria'' was created in 1994 by Chatterjee and Ben Creisler. The specific name ''maleriensis'' is a reference to the Maleri Formation, in southern India, where its fossils were found. Description The only known specimen, holotype ISI R306 is incomplete and consists of parts of the front ends of the upper and lower jaws, 28 incomplete vertebrae from all parts of the spinal column, most of a femur, and an astragalus (ankle bone). The partial skull is about 4 centimeters long (1.5 in). Although material of ''Alw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silesauridae
Silesauridae is an extinct family of Triassic dinosauriforms. It is most commonly considered to be a clade of non-dinosaur dinosauriforms, and the sister group of dinosaurs. Some studies have instead suggested that most or all silesaurids comprised an early diverging clade or a paraphyletic grade within ornithischian dinosaurs. Silesaurids have a consistent general body plan, with a fairly long neck and legs and possibly quadrupedal habits, but most silesaurids are heavily fragmentary nonetheless. Furthermore, they occupied a variety of ecological niches, with early silesaurids (such as '' Lewisuchus'') being carnivorous and later taxa (such as ''Kwanasaurus'') having adaptations for specialized herbivory. As indicated by the contents of referred coprolites, '' Silesaurus'' may have been insectivorous, feeding selectively on small beetles and other arthropods. Classification Silesauridae is typically considered the sister group to Dinosauria. The group was named in 2010 by Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herrerasauria
Saurischia ( , meaning "reptile-hipped" from the Greek ' () meaning 'lizard' and ' () meaning 'hip joint') is one of the two basic divisions of dinosaurs (the other being Ornithischia), classified by their hip structure. Saurischia and Ornithischia were originally called orders by Harry Seeley in 1888 though today most paleontologists classify Saurischia as an unranked clade rather than an order.Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). (2004). ''The Dinosauria. 2nd edition''. University of California Press, Berkeley. 833 pp. Description All carnivorous dinosaurs (certain types of theropods) are traditionally classified as saurischians, as are all of the birds and one of the two primary lineages of herbivorous dinosaurs, the sauropodomorphs. At the end of the Cretaceous Period, all saurischians except the birds became extinct in the course of the Cretaceous–Paleogene extinction event. Birds, as direct descendants of one group of theropod dinosaurs, are a sub-clad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guaibasauridae
Guaibasauridae is a family of basal sauropodomorph dinosaurs, known from fossil remains of late Triassic period formations in Brazil and Argentina. Classification The exact makeup and classification of the Guaibasauridae remain uncertain. The family was originally named by Jose Bonaparte and colleagues in 1999 to contain a single genus and species, ''Guaibasaurus candelariensis''. When the second specimen of ''Guaibasaurus'' was described from better remains in 2007, it became easier to compare it to other enigmatic early saurischians, which are often difficult to classify because they combine characteristics of the two major saurischian groups, Theropoda and Sauropodomorpha. Bonaparte and colleagues, in light of the information gained from this second specimen, found that the genus ''Saturnalia'' (which is anatomically very similar to ''Guaibasaurus'') could also be assigned to the Guaibasauridae, though they did not conduct a phylogenetic analysis or define Guaibasauridae as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thecospondylus
''Thecospondylus'' (THEEK-o-SPON-di-lus, "sheath vertebra") is a dubious genus of dinosaur from the Early Cretaceous of England. Scientists are unsure as to whether ''Thecospondylus'' was a saurischian or an ornithischian. History Dr. A.C. Horner, an amateur geologist living at Tonbridge, in the nineteenth century acquired a fossil found in the quarry of Southborough. He sent it to paleontologist Harry Govier Seeley who in 1882 described and named it as the type species ''Thecospondylus horneri''. The genus name is derived from Greek ''theke'' meaning 'sheath' and ''spondylos'' meaning 'vertebra', a reference to the "extremely thin" bone forming the vertebrae. The specific name honours Horner. The holotype, BMNH R.291, was found in a layer of the Hastings Sand, sandstone dating from the Valanginian - Hauterivian. It consist of an elongated natural internal cast or endocast of the neural canal of the sacrum, about sixty centimetres long. It shows the divisions of at least fiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tawa Hallae
''Tawa'' (named after the Hopi word for the Puebloan sun god) is a genus of possible basal theropod dinosaurs from the Late Triassic period. The fossil remains of ''Tawa hallae'', the type and only species were found in the Hayden Quarry of Ghost Ranch, New Mexico, US. Its discovery alongside the relatives of ''Coelophysis ''and ''Herrerasaurus'' supports the hypothesis that the earliest dinosaurs arose in Gondwana during the early Late Triassic period in what is now South America, and radiated from there around the globe. The specific name honours Ruth Hall, founder of the Ghost Ranch Museum of Paleontology. Description ''Tawa'' was estimated to have been long as an adult, with a weight of . ''Tawa'' preserves characters that can be associated with different dinosaur taxa. Its skull morphology resembles that of coelophysoids and the ilium approximates that of a herrerasaurid. Like the coelophysoids, ''Tawa'' has a kink in its upper jaws, between the maxilla and the premax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smok (archosaur)
''Smok'' (meaning "dragon" in Polish language, Polish) is an extinct genus of large carnivorous archosaur. It lived during the Late Triassic, latest Triassic period (geology), period (latest Norian to early Rhaetian stage, between 205–200 mya (unit), Ma). Its remains have been found in Lisowice, Silesian Voivodeship, Lisowice, southern Poland. The Monotypic taxon, only species is ''Smok wawelski'' (after the Wawel Dragon, a dragon from Polish folklore) and was named in 2012 in paleontology, 2012. It is larger than any other known predatory archosaur from the Late Triassic or Early Jurassic of central Europe. The relation of ''Smok'' to other archosaurs has not yet been thoroughly studied; it may be a rauisuchidae, rauisuchid, prestosuchidae, prestosuchid, an ornithosuchid pseudosuchian (part of the crocodilian lineage of archosaurs) or a theropod dinosaur (part of the bird/dinosaurian lineage of archosaurs). Description At an estimated in length, ''Smok'' was the largest car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pisanosaurus
''Pisanosaurus'' () is an extinct genus of early dinosauriform, likely an ornithischian or silesaurid, from the Late Triassic of Argentina. It was a small, lightly built, ground-dwelling herbivore, that could grow up to an estimated long. Only one species, the type, ''Pisanosaurus mertii'', is known, based on a single partial skeleton discovered in the Ischigualasto Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina. This part of the formation has been dated to the late Carnian, approximately 229 million years ago. Discovery and naming ''Pisanosaurus'' is known from a single fragmented skeleton discovered in 1962 by Galileo Juan Scaglia at the Hoyada del Cerro Las Lajas locality (also known as Agua de Las Catas) in the Ischigualasto Formation of La Rioja Province, Argentina. The genus is based on a specimen given the designation PVL 2577, which consists of a partial skull including a fragmentary right maxilla with teeth, and incomplete right ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nyasasaurus
''Nyasasaurus'' (meaning " Lake Nyasa lizard") is an extinct genus of avemetatarsalian archosaur from the putatively Middle Triassic Manda Formation of Tanzania that may be the earliest known dinosaur. The type species ''Nyasasaurus parringtoni'' was first described in 1956 in the doctoral thesis of English paleontologist Alan J. Charig, but it was not formally described until 2013. Previously, the oldest record of dinosaurs was from Brazil and Argentina and dated back to the mid-late Carnian stage, about 233.23 to 231.4 million years ago. ''Nyasasaurus'' comes from a deposit formerly considered Anisian in age, meaning that it would predate other early dinosaurs by about 12 million years. However, more recent studies cast doubt to this age, pointing out that the deposits would actually be Carnian in age, which would considerably reduce this temporal gap. History of study In the 1930s, the holotype of ''Nyasasaurus'' was collected in Parrington's locality B36 from the Lifua Memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nhandumirim
''Nhandumirim'' (meaning "small rhea" in the Tupi language) is a genus of basal sauropodomorph dinosaur from the Carnian age of Late Triassic Brazil. It is currently considered a saturnaliid sauropodomorph. The type and only species, ''Nhandumirim waldsangae,'' is known from a single immature specimen including vertebrae, a , pelvic material, and a hindlimb found in the Santa Maria Formation in Rio Grande do Sul. ''Nhandumirim'' is differentiated from other Santa Maria dinosaurs such as ''Staurikosaurus'' and ''Saturnalia'' on the basis of its more gracile, long-legged proportions and several more specific skeletal features. However, it is noteworthy that the holotype of ''Nhandumirim'' is an immature individual. Several features of the tibia led the describers of the genus and species to consider ''Nhandumirim'' ''waldsangae'' possibly the earliest theropod, but some analyses in their study offer alternative positions within Saurischia. All subsequent studies considered ''Nh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eodromaeus
''Eodromaeus'' (meaning "dawn runner") is an extinct genus of probable basal theropod dinosaurs from the Late Triassic of Argentina. Like many other of the earliest-known dinosaurs, it hails from the Carnian-age (~230 Ma) Ischigualasto Formation, within the Ischigualasto-Villa Unión Basin of northwestern Argentina. Upon its discovery, it was argued to be one of the oldest true theropods, supplanting its contemporary ''Eoraptor'', which was reinterpreted as a basal sauropodomorph.Martínez et al., 2011 Discovery Fossils from ''Eodromaeus'' were first discovered in 1996 by Argentinean paleontologist Ricardo N. Martinez and Earthwatch volunteer Jim Murphy, and it was first believed that the fossils were a new species of ''Eoraptor''. However, as the researchers started to take a closer look at the fossils, they found that it had many skeletal features which were absent in ''Eoraptor'', and they understood that it came from a new genus. ''Eodromaeus'' is known from six specimen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
