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The longest complete dinosaur is the 27 meters (89 ft) long ... which has been dated to 66.038 ± 0.025 million years ago, [272] fossils of non-avian dinosaurs ...
End Triassic: 200 million years ago, 80% of species lost, including all conodonts; End Cretaceous: 66 million years ago, 76% of species lost, including all ammonites, mosasaurs, plesiosaurs, pterosaurs, and nonavian dinosaurs; Smaller extinction events have occurred in the periods between, with some dividing geologic time periods and epochs.
In October 2019, researchers asserted that the event rapidly acidified the oceans and produced long-lasting effects on the climate, detailing the mechanisms of the mass extinction. [15] [16] Other causal or contributing factors to the extinction may have been the Deccan Traps and other volcanic eruptions, [17] [18] climate change, and sea level ...
Buckland, like others at the time, did not grasp how long ago dinosaurs lived, believing Earth to be only a few thousand years old. Scientists now know Earth is about 4.5 billion years old ...
The Mesozoic Era [3] is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods.It is characterized by the dominance of gymnosperms such as cycads, ginkgoaceae and araucarian conifers, and of archosaurian reptiles such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea.
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.
In turn, this phase led to the evolution of the giant carnivorous dinosaurs beloved by movie directors and childhood books at the beginning of the Jurassic Period 200 million years ago. The ...
Most Triassic dinosaurs were small predators and only a few were common, such as Coelophysis, which was 1 to 2 metres (3.3 to 6.6 ft) long. Triassic sauropodomorphs primarily inhabited cooler regions of the world. [63] The large predator Smok was most likely also an archosaur, but it is uncertain if it was a primitive dinosaur or a pseudosuchian.