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They are currently the most successful and diverse group of living reptiles, with more than 10,000 extant species. The only major group of terrestrial lizards to go extinct at the end of the Cretaceous were the polyglyphanodontians, a diverse group of mainly herbivorous lizards known predominantly from the Northern Hemisphere. [109]
Spinosaurus (/ ˌ s p aɪ n ə ˈ s ɔːr ə s /; lit. ' spine lizard ') is a genus of spinosaurid dinosaur that lived in what now is North Africa during the Cenomanian stage of the Late Cretaceous period, about 100 to 94 million years ago.
Juvenile spinosaurid fossils are somewhat rare. However, an ungual phalanx measuring 21 mm (0.83 in) belonging to a very young Spinosaurus indicates that Spinosaurus, and probably by extent other spinosaurids, may have developed their semiaquatic adaptations at birth or at a very young age and maintained the adaptations throughout their lives ...
Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods.. While Carnosauria was historically considered largely synonymous with Allosauroidea, some recent studies have revived Carnosauria as clade including both Allosauroidea and Megalosauroidea (which is sometimes recovered as paraphyletic with respect to Allosauroidea), and thus ...
Definite evidence of Late Cretaceous sauropods in North America was first discovered in 1922, when Charles Whitney Gilmore described Alamosaurus sanjuanensis. [1] The term "sauropod hiatus" was coined by researchers Spencer G. Lucas and Adrian P. Hunt in 1989 to describes how fossils of the clade become scarce in western North America near the beginning of the Late Cretaceous.
Phytosaurs are generally regarded as the most basal group of Crurotarsi, a clade of archosaurs that includes crocodilians and their extinct relatives. [ 27 ] [ 28 ] [ 29 ] Phytosaurs are often excluded from a clade called Suchia , which usually encompasses all other crurotarsans, including aetosaurs , rauisuchians , and crocodylomorphs . [ 29 ]
Artist's depiction of the end-Cretaceous impact eventSince the 19th century, a significant amount of research has been conducted on the Cretaceous–Paleogene extinction event, the mass extinction that ended the dinosaur-dominated Mesozoic Era and set the stage for the Age of Mammals, or Cenozoic Era.
Why this is remains unclear, but some similarities in feeding niches between iguanodontians, hadrosauroids and sauropods have been suggested and may have resulted in some competition. However, this cannot fully explain the full decline in distribution of sauropods, as competitive exclusion would have resulted in a much more rapid decline than ...