Ornithischia

Ornithischia is one of the major groups of dinosaurs, known for characteristics like a beak-like mouth and often herbivorous diets. This group includes well-known dinosaurs like Triceratops and Stegosaurus. Ornithischians generally walked on two or four legs and exhibited a range of body shapes and sizes. They thrived during the Mesozoic Era and were diverse in their adaptations, including some that could defend themselves with armor or horns. Their name, meaning "bird-hipped," reflects certain hip bone structures, although they are not directly related to modern birds. Ornithischians played a significant role in prehistoric ecosystems.