Dinosaur
Dinosaurs (clade Dinosauria) were large reptiles that roamed the Earth for over 170 million years (from 237 to 66 million years ago). The first dinosaur, Megalosaurus, was discovered in 1824. The Chicxulub asteroid would later wipe all of them out, except for the birds.
Animals confused with Dinosaurs
[edit | edit source]However, many reptiles are confused for dinosaurs, like the flying reptiles. Pterosaurs (commonly called 'pterodactyls') were closely related to dinosaurs but weren't. The marine reptiles (ichthyosaurs, plesiosaurs, mosasaurs, etc...) weren't related at all, being in many groups. Dimetrodon isn't even a reptile, but a proto-mammal, or synapsid.