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Gallimimus bullatus

Gallimimus bullatus ("chicken mimic") roamed the Late Cretaceous landscape of Mongolia 70 million years ago. These fleetfooted dinosaurs were much like modern ostriches and emus. In fact, Gallimimus belongs to the most bird-like of all dinosaur groups: the Coelurosaurs, and it is from this group that scientists now believe that birds arose.

Most theropod dinosaurs (and Gallimimus was a theropod) are distinguished by their curved, serrated teeth that were obviously designed for eating meat. You'll see such teeth in T. rex, Allosaurus and Deinonychus to name but a few. Gallimimus had a beak Its toothless mouth was probably covered by horn-like material similar to the beak of modern birds. The consensus among scientists is that Gallimimus was an omnivore, living off small lizards, reptiles and mammals, along with insects and some plants. It probably swallowed its prey whole.

Gallimimus had powerful legs that supported a compact body. Its rigid tail acted as a counterbalance to the horizontal body and long neck when it ran in pursuit of its dinner. Its long arms had three 5" claws for grasping and holding.

Location
This ostrich-like dinosaur from Central Asia was similar to our modern flightless birds. While toothless, it is related to the meat-eating giants such as T. rexand Allosaurus.

Taxonomy
The taxonomic relationships of dinosaurs are a complicated arrangement full of long Greek and Latin words. This complex system helps us understand which dinosaurs are related to one another as well as the characteristics they have in common. The systematics of a specimen tell the story of its lineage and evolutionary relationships. Among dinosaurs, Gallimimus is a theropod. This large group (Suborder) includes most of the well know meat-eating dinosaurs. Theropods are further divided into at least three smaller groups: ceratosaurs, carnosaurs, and coelurosaurs.

Gallimimus' path leads through coelurosaurs to the ornithomimosaurs. The other two coelurosaur families are dromaeosaurs and oviraptorosaurs. The ornithomimosaurs are the most abundant group of coelurosaurs. Gallimimus bullatus, the specimen you are holding, is a typical late Cretaceous Ornithomimosaur from Central Asia. Struthiomimus altus is typical of the same period in N. America.

Ornithomimosaurs are distinguished from other coelurosaurs by their lightly built skull, very large orbits (opening around the eye), a shallow snout, the lack of teeth and a long neck. Gallimimus posessed all of these traits.

Other features of Gallimimus illustrate characteristics of the broader group of coelurosaurs: very flexible neck joints which allowed the neck to move freely; belly ribs (gastralia) that protected the abdomen; and deep ligament scars on the spines of the dorsal vertebrae. These ligaments and the gastralia (belly ribs) would have helped stabilize the abdomen and hold it forward and nearly horizontal as the dinosaur ran. Large attachment sites for muscles on the end of the tail would have helped to hold the tail rigid as a counterbalance to the forward leaning body.

When we move up to the even broader category of theropods, we find that skulls, like Gallimimus, were attached to the neck at a very flexible joint that allowed rapid and precise movement of the head. This supports the notion that theropods were sophisticated, visually oriented hunters. Modern birds have head-neck joints similar to their theropod ancestors.

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