Ornithomimosauria

Ornithomimosauria is a clade of theropod dinosaurs within Coelurosauria, commonly called “bird-mimics” for their ostrich-like build. The group includes several families, most notably Ornithomimidae (featuring genera such as Ornithomimus, Struthiomimus, and Gallimimus) and more basal lineages such as Garudimimidae (Garudimimus, Harpymimus) and Deinocheiridae (Deinocheirus).

Anatomy and adaptations of ornithomimosaurs were largely geared toward speed and endurance. They typically had slender, elongated limbs, a light body, a small skull with a beak in many species, long necks and tails, and large eyes. Forelimbs were relatively long and may have assisted in foraging or manipulation. Feathers are known in several taxa, indicating plumage similar to that of modern birds. Most species lacked teeth in the beak region, though some early relatives retained small teeth.

Temporal and geographic range: Ornithomimosaurs lived from the Early to Late Cretaceous, roughly 125 to 66 million years ago. Fossils have been found in North America, Asia, and Europe, with Mongolia yielding several well-known taxa. The group displays considerable diversity in size and form across continents.

Ecology and behavior: They are interpreted as fast-running, cursorial dinosaurs. Diets are thought to have been omnivorous or herbivorous, with beaked mouths suitable for cropping vegetation, seeds, and fruits, and possibly small animals in some species. Their ecological roles likely varied with species and habitat.

Notable genera: Ornithomimus, Struthiomimus, Gallimimus, Deinocheirus, Garudimimus, Harpymimus.