
Dinosaur | Definition, Types, History, Names, & Facts | Britannica
Mar 1, 2026 · 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 …
Dinosaur - Extinction, Fossils, Evolution | Britannica
Jan 28, 2026 · Dinosaur - Extinction, Fossils, Evolution: Dinosaurs lived in many kinds of terrestrial environments, and although some remains, such as footprints, indicate where dinosaurs actually …
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 …
Dinosaur - Evolution, Classification, Extinction | Britannica
Mar 1, 2026 · 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 …
Dinosaur - Archosaurs, Reptiles, Triassic | Britannica
Mar 1, 2026 · Dinosaurs are currently defined as Triceratops (representing Ornithischia), birds (representative of Saurischia), and all the descendants of their most recent common ancestor. …
Classification of dinosaurs and theories for their extinction | Britannica
dinosaur, Any of the extinct reptiles that were the dominant land animals during most of the Mesozoic Era (251–65.5 million years ago).
Dinosaur - Extinction Causes, Evidence, & Theory | Britannica
Mar 1, 2026 · 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 …
Dinosaur - Reptiles, Extinction, Fossils | Britannica
Feb 20, 2026 · 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 …
How Long Did Dinosaurs Live? - Britannica
This initial period of dinosaur evolution set the stage for their dominance in the Mesozoic Era. Throughout the Mesozoic Era, which lasted from about 252.2 million to 66 million years ago, …
dinosaur - Students | Britannica Kids | Homework Help
The name dinosaur comes from the Greek words deinos (“terrible” or “fearfully great”) and sauros (“reptile” or “lizard”). Scientists have discovered and named some 1,000 dinosaur species. New …