Dating of the triassic period
Spinosaurus was among the largest of all known carnivorous dinosaurs, nearly as large as or even larger than Tyrannosaurus, Giganotosaurus and Carcharodontosaurus.
Velociraptor is a genus of dromaeosaurid theropod dinosaur that lived approximately 75 to 71 million years ago during the latter part of the Cretaceous Period.
Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 68 million years ago (mya) in what is now North America.
It was the last known member of the tyrannosaurids, and among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event.
It shared its environment with at least three other sauropod genera, which might have exploited different food sources in order to reduce competition.
Amargasaurus probably fed at mid-height, as shown by the orientation of its inner ear and the articulation of its neck vertebrae, which suggest a habitual position of the snout 80 centimeters above the ground and a maximum height of 2.7 meters.
Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942.
At about 7 meters in length, with a weight of about 400 kilograms, Dilophosaurus was one of the earliest large predatory dinosaurs, though it was smaller than some later theropods.