The term 'dinosaur' originates from the Greek words deino and sauros, meaning 'terrible' and 'lizard'.Sir Richard Owen invented the name 'dinosaur' in 1842, to describe an extinct group of terrestrial reptiles that lived during the Mesozoic. At that time, he had only three or four dinosaur skeletons to consider, but many hundreds more have been found since 1842.
Dinosaurs show a range of adaptations to a wide range of environments and conditions, and as a result they became the most successful land animals of all time.Dinosaurs are animals that dominated the terrestrial ecosystem for over 100-million years. Non-avian dinosaurs became extinct 65 million years ago (Mya) at the end of the Cretaceous period.
Dinosaurs are known from both fossils and nonfossils including fossilized bones, feces, trackways, gastroliths, feathers, impressions of skin and internal organs, and "soft tissues, including blood vessels and cells lining them. Since the first dinosaur was recognized in the 19th century, their mounted.