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Dinosaurs are a diverse group of reptiles [note 1] of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 ...
In the TJME's aftermath, dinosaurs experienced a major radiation, filling some of the niches vacated by the victims of the extinction. [7] Crocodylomorphs likewise underwent a very rapid and major adaptive radiation. [5] Surviving non-mammalian synapsid clades similarly played a role in the post-TJME adaptive radiation during the Early Jurassic ...
Alternatively, interpretation based on the fossil-bearing rocks along the Red Deer River in Alberta, Canada, supports the gradual extinction of non-avian dinosaurs; during the last 10 million years of the Cretaceous layers there, the number of dinosaur species seems to have decreased from about 45 to approximately 12. Other scientists have made ...
A study aiming to quantify the habitat of latest Cretaceous North American dinosaurs, based on data from fossil occurrences and climatic and environmental modelling, and evaluating its implications for inferring whether dinosaur diversity was in decline prior to the Cretaceous–Paleogene extinction event, was published by Chiarenza et al ...
All non-avian dinosaurs became extinct during that time. [20] The boundary event was severe with a significant amount of variability in the rate of extinction between and among different clades. Mammals, descended from the synapsids, and birds, a side-branch of the theropod dinosaurs, emerged as the two predominant clades of terrestrial tetrapods.
The amount of dust strangling the atmosphere is thought to have been about 2,000 gigatonnes; more than 11 times the weight of Mount Everest. Researchers ran simulations on sediment found at a ...
As scientists have discerned from fossil records, species on Earth have already passed through five mass extinction events in the planet’s lifetime, including the last mass extinction roughly 65 ...
Major extinctions in terrestrial vertebrates and large amphibians. Earliest examples of armoured dinosaurs. 195 Ma First pterosaurs with specialized feeding (Dorygnathus). First sauropod dinosaurs. Diversification in small, ornithischian dinosaurs: heterodontosaurids, fabrosaurids, and scelidosaurids. 190 Ma Pliosauroids appear in the fossil ...