Gallimimus is a genus of extinct ornithomimid theropod dinosaurs that lived 71 to 69 million years ago. It is one of the largest ornithomimosaurs to have ever walked on earth.

Discovery and Species

The first fossil remains of Gallimimus were unearthed in August 1963 by a team led by Professor Zofia Kielan-Jaworowska during a Polish-Mongolian expedition in Gobi Desert, Mongolia. The findings were reported in a 1965 paper. The holotype specimen (IGM 100/11) had partial skeleton including lower jaws and the skull. The specimen was described and named by paleontologists Halszka Osmólska, Rinchen Barsbold and Ewa Roniewicz. Gallimimus bullatus, the type species, is the one and only described species belonging to this genus.

In 1996, Mongolian paleontologist and geologist Rinchen Barsbold named another species Gallimimus mongoliensis based on a specimen (IGM 100/14) found in older Bayanshiree Formation. But, it was not formally assigned to this genus. In 2006, further analysis by Barsbold suggested that specimen IGM 100/14 does not belong to genus Gallimimus; instead, it belongs to another unnamed ornithomimid genus.

Physical Characteristics

Gallimimus’ appearance was quite like that of the modern-day ostrich (possibly carrying feathers also). Unlike other ornithomimids, it had a small and exceptionally elongated skull. They had a snout similar to the appearance of modern-day goose – planate near the end. They also possessed large eyes, toothless beak, a long neck, short arms, long fingers, long legs as well as a long tail. Its eyes were placed on the sides of their head, suggesting that they did not have binocular vision. They had strong ilium, long limbs, short toes, heavy tail base, a long tibia and metatarsus. Its bones were hollow.

Etymology

The generic term Gallimimus has derived from Latin words gallus meaning “chicken”, and mimus meaning “mimic.” The name is in reference to the neural arches of the front neck vertebrae that match those of the Galliformes.

The specific name ‘bullatus‘ (of the type species Gallimimus bullatus) has derived from Latin word bulla, referring the bulbous lump in the braincase on the underside of the parasphenoid, forming a capsule type shape.

Habitat and Behavior

Nemegt Formation’s rock facies suggest that they lived near river channels, streams, shallow lakes or mudflats. They probably used to stay in flocks. The mesic environments offered a diverse range of foods. It is believed that they were swift runners. The lower portions of their legs were long that helped them to cover a lot of grounds in each step. The tail was used as a counterbalance while running.

Diet

There are several conflicting theories when it comes to Gallimimus’s feeding habits. The first researchers suggested that they preyed upon small animals. However later, different theories suggested both herbivorous and omnivorous adaptations. Some authors suggested, they probably depended on filter feeding. In 2005, a paper published by Barrett said that Gallimimus was more likely to be herbivorous as filter feeding would cost a lot of energy for an animal as big.

Interesting Facts

• In 2001, Norwegian researcher Jørn H. Hurum suggested that their jaw bones were paper thin.
• Gallimimus has been depicted in several documentary films, movies (e.g. Jurassic Park and The Lost World: Jurassic Park), video games (e.g. Minecraft and Lego Jurassic World) and toy lines.
• They probably shared their territory with predators like Tarbosaurus.