Ornithoid

The term ornithoid refers to a group of theropod dinosaurs that share characteristics with birds. The term was coined by zoologist Thomas Henry Huxley in 1869 to describe a series of Jurassic and Cretaceous dinosaurs that exhibited bird-like features. These characteristics include hollow bones, three-toed limbs, and wishbone-shaped collarbones, all of which are traits that are also present in modern birds.

Ornithoid dinosaurs were a diverse group, with many different species found on different continents. They ranged in size from small, insectivorous predators to large, herbivorous sauropodomorphs. Some of the most well-known ornithoid dinosaurs include Archaeopteryx, Oviraptor, and Ornithomimus.

One of the defining features of ornithoid dinosaurs is their ability to fly. While not all ornithoid dinosaurs were capable of flight, many species are believed to have been gliders or parachutists, using their long arms and wings to slow their descent. The presence of feathers is also a characteristic of ornithoid dinosaurs, with many species exhibiting quill knobs, the bumps on the bone where feathers attach.

The ornithoid dinosaurs are often seen as a intermediate stage between the non-avian theropods and the modern birds. Studies have shown that the avian characteristics of ornithoid dinosaurs are more advanced than those of their non-avian relatives, suggesting that the ability to fly and the presence of feathers may have evolved independently in several different lineages.