The Bird-Footed Dinosaurs: Ornithopods—A Worldwide Success Story of Astonishing Diversity and Survival.

Ornithopoda is a group of herbivorous dinosaurs belonging to the order Ornithischia, represented by famous species such as Iguanodon and Parasaurolophus.
Appearing in the Early Jurassic of the Mesozoic Era, they distributed across almost the entire world, including Antarctica, and flourished greatly until the mass extinction at the end of the Cretaceous.

Distributed across almost the entire world, they flourished greatly.

Ornithopods are known as one of the most successful groups of herbivorous dinosaurs throughout the dinosaur era.

Characteristics and Evolution: Diversity as the Key to Success

Diversity in characteristics and evolution

Due to their high adaptability, ornithopods ranged in size from small species of about 1 meter in length to large species exceeding 10 meters, such as those in the Hadrosaurus family (duck-billed dinosaurs).

Locomotion Style

They were characterized primarily by bipedalism, but larger species could switch between bipedal and quadrupedal walking, using four legs to support their weight.

Diet

Possessing a beak at the tip of their mouths and developed teeth (such as dental batteries), they could grind food finely, allowing them to eat even tough plants efficiently.

Evolutionary Diversity

Ornithopods adapted to a wide range of regions and eras, becoming one of the most widespread dinosaur groups in Earth’s history.

Historical Confusion Surrounding Classification

Because the trait of bipedalism was ancestral to all ornithischians, the group Ornithopoda historically became a “wastebasket taxon” where early species of other groups, such as the Lesothosaurus family and primitive thyreophorans, were mistakenly included.
However, with scientific advancements, species classification has been refined, and their diverse evolutionary paths are becoming clearer.