what is dinosaur

Dinosaurs were a diverse group of ancient reptiles that lived on land. The name Dinosauria was introduced by the British anatomist Richard Owen in 1842; it means “terrible lizards.” [citation_1ux4wk] They included plant-eaters such as sauropods and armored dinosaurs, as well as meat-eating theropods. Sauropods were especially large: they were the largest terrestrial vertebrates known, and some may have reached about 40 meters in length. [citation_12wntj] [citation_13yhvs]

Dinosaurs were not all alike: some walked on two legs, others on four; some had armor, plates, horns, or long necks. Their fossils show that they occupied many ecological roles, including different feeding niches among large herbivores. [citation_1ux4wl] [citation_1ux4wr] In everyday speech, “dinosaur” usually means these extinct animals, especially the non-avian dinosaurs that disappeared at the end of the Cretaceous period. [citation_1ux4wq]