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Dinosaurs have always been recognized as an extremely varied group: over 900 non-avian dinosaur genera have been confidently identified (2018) with 1124 species (2016). Estimates put the total number of dinosaur genera preserved in the fossil record at 1850, nearly 75% still undiscovered, [ 20 ] [ 21 ] [ 22 ] and the number that ever existed ...
Mounted skeletons of Tyrannosaurus (left) and Apatosaurus (right) at the AMNH. 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, although the exact origin and timing of the evolution of dinosaurs is the subject of active research.
Though no Tyrannosaurus sclerotic ring has been found, Kenneth Carpenter estimated its size based on that of Gorgosaurus. The inferred sclerotic ring for the Stan specimen is ~7 cm (2.8 in) in diameter with an internal aperture diameter of ~3.5 cm (1.4 in). Based on eye proportions in living reptiles, this implies a pupil diameter of about 2.5 ...
Sue[a] (stylized: SUE) is the nickname given to FMNH PR 2081, which is one of the largest, [b] most extensive, and best preserved Tyrannosaurus rex specimens ever found, at over 90 percent recovered by bulk. [4] FMNH PR 2081 was discovered on August 12, 1990, [5] by American explorer and fossil collector Sue Hendrickson, and was named after her ...
Fossils of Tawa-like dinosaurs have also been found in South America, which has important indications about paleogeography. During the Early Jurassic Period, dinosaurs such as Dilophosaurus, Anchisaurus, Coelophysis (formerly known as Megapnosaurus), and the early thyreophoran Scutellosaurus lived in North America.
Ott & Larson, 2010. Triceratops (/ traɪˈsɛrətɒps / try-SERR-ə-tops; [1] lit. 'three-horned face') is a genus of chasmosaurine ceratopsian dinosaur that lived during the late Maastrichtian age of the Late Cretaceous period, about 68 to 66 million years ago in what is now western North America. It was one of the last-known non-avian ...
Traces of dinosaurs have been found in Arizona in the form of bones and footprints. There are preserved three-toed dinosaur footprints that are around 200 million years old near Tuba City on the ...
Classification of dinosaurs. Dinosaur classification began in 1842 when Sir Richard Owen placed Iguanodon, Megalosaurus, and Hylaeosaurus in "a distinct tribe or suborder of Saurian Reptiles, for which I would propose the name of Dinosauria." [1] In 1887 and 1888 Harry Seeley divided dinosaurs into the two orders Saurischia and Ornithischia ...