Dinosaur | Definition, Types, History, Names, & Facts | Britannica
2024年11月20日 · dinosaur, (clade Dinosauria), the common name given to a group of reptiles, often very large, that first appeared roughly 245 million years ago (near the beginning of the Middle Triassic Epoch) and thrived worldwide for nearly 180 million years.
Dinosaur - Archosaurs, Reptiles, Triassic | Britannica
2024年11月20日 · Dinosaurs are currently defined as Triceratops (representing Ornithischia), birds (representative of Saurischia), and all the descendants of their most recent common ancestor. Dinosaur studies include phylogenetic analyses, functional anatomic studies, and mechanical and theoretical models.
Dinosaur - Evolution, Classification, Extinction | Britannica
2024年11月20日 · Dinosaur - Evolution, Classification, Extinction: After dinosaurs were recognized as a new type of fossil animal, popular fascination with them reached a peak in the 1850s with the first attempts to reconstruct Iguanodon, Megalosaurus, and Hylaeosaurus.
Dinosaurs Portal | Britannica
Dinosaur, the common name given to a group of reptiles, often very large, that first appeared roughly 245 million years ago (near the beginning of the Middle Triassic Epoch) and thrived worldwide for nearly 180 million years.
Dinosaur - Reptiles, Extinction, Fossils | Britannica
2024年11月20日 · Dinosaur - Reptiles, Extinction, Fossils: The chief difference between the two major groups of dinosaurs is in the configuration of the pelvis. The two dinosaurian orders were named Saurischia and Ornithischia in 1887.
Dinosaur - Extinction, Fossils, Evolution | Britannica
2024年11月20日 · Dinosaur - Extinction, Fossils, Evolution: Dinosaurs lived in many kinds of terrestrial environments, and although some remains, such as footprints, indicate where dinosaurs actually lived, their bones tell us only where they died.
Tyrannosaurus rex | Description, Dinosaur, & Facts | Britannica
2024年11月1日 · Turannosaurus rex, species of large predatory theropod dinosaurs that lived during the end of the Cretaceous Period (about 66 million years ago) known from fossils found in the United States and Canada dating to between about 80 million and 66 million years ago.
dinosaur - Kids | Britannica Kids | Homework Help
Some animals lived through the time when the dinosaurs disappeared. The ancestors of today’s frogs, turtles, lizards, and snakes found a way to survive. Birds also survived. Scientists do not know why some animals lived but dinosaurs did not.
Titanosaurs: 8 of the World's Biggest Dinosaurs | Britannica
The largest dinosaurs of the era were the sauropods, a collection of four-legged herbivorous species that possessed long necks and tails. A sauropod subgroup called the Titanosauria contained the largest sauropods.
Dinosaur - Extinction Causes, Evidence, & Theory | Britannica
2024年11月20日 · Dinosaur - Extinction Causes, Evidence, & Theory: The mass extinction of dinosaurs 66 million years ago remains a misconception; the fossil record shows that dinosaurs were already in decline during the late Cretaceous.