Dinosaurs

Characters (or more accurately, animals) that belong to the clade Dinosauria, which includes 2 Orders Saurischia and Ornithischia.

Note that not all reptiles from the Mesozoic era (such as pterosaurs, mosasaurs, plesiosaurs, etc) or any prehistoric reptilian-looking animals (e.g Dimetrodon) are dinosaurs as commonly mistaken, so do not add this category to any prehistoric animal that is not a dinosaur.