Ornithischian Dinosaur -

: Inset tooth rows that formed cheeks, allowing them to hold and grind food efficiently.

: Bony tendons that crisscrossed the vertebrae to stiffen the tail and back for stability. Hall of Ornithischian Dinosaurs | AMNH ornithischian dinosaur

: A backward-pointing pubis bone, parallel to the ischium, likely evolved to accommodate a larger digestive system for processing plants. : Inset tooth rows that formed cheeks, allowing

: A unique, beak-like bone at the tip of the lower jaw used for cropping vegetation. : A unique, beak-like bone at the tip

Ornithischian dinosaurs , or "bird-hipped" dinosaurs, represent one of the two primary orders of dinosaurs. Despite the name, they are not the direct ancestors of modern birds—those actually evolved from the "lizard-hipped" saurischian group. This diverse group was almost exclusively herbivorous and is famous for its elaborate physical adaptations, including horns, armor, and complex chewing mechanisms. Key Defining Features