'''Gallimimus''' (gal-ih-MY-mus) , meaning 'fowl mimic', is a
genus of
ornithomimosaurid
dinosaur from the late
Cretaceous Period (
Maastrichtian stage)
Nemegt Formation of
Mongolia. With a maximum length of 4 to 6
meters (13-20
feet) and weighing as much as 440
kilograms (970
pounds), it was one of the largest ornithomimosaurs. ''Gallimimus'' is known from multiple individuals, ranging from juvenile (about 0.5 metres tall at the hip) to adult (about 2 metres tall at the hip).
The
fossil remains of this
dinosaur were discovered in the early
1970s in the
Gobi Desert of Mongolia. In
1972, it was named by
paleontologists
Rinchen Barsbold, Halszka Osmólska, and Ewa Roniewicz. The only known species is ''Gallimimus bullatus''. A supposed second species, "''Gallimimus mongoliensis''", has never been formally referred to this genus. A recent reanalysis of the nearly complete skeleton of ''Gallimimus mongoliensis'' concluded that it is not a species of ''Gallimimus'' but may represent a new, currently unnamed
ornithomimid genus (Kobayashi & Barsbold, 2006).
''Gallimimus'' was rather
ostrich-like, with a small head, large eyes, a long neck, short arms, long legs, and a long tail. A diagnostic character of ''Gallimimus'' is a distinctly short 'hand' relative to the
humerus length, when compared to other ornithomimids. The tail was used as a counter-balance. The eyes were located on the sides of its head, meaning that it did not possess
binocular vision. Like most modern birds, it had hollow bones. ''Gallimimus'' had a number of adaptations which suggest good running ability, such as long limbs, a long
tibia and
metatarsus and short toes but it is unknown how fast it could run.
A fossilized beak is present in one ''Gallimimus'' skull and ridges on the beak have been interpreted as part of a duck-like filter-feeding mechanism. However, similar ridges are seen in herbivorous
sea turtles and ornithomimids were relatively common in seasonally dry environments, where filter-feeding was probably not a viable lifestyle. It seems more probable that ''Gallimimus'' was an omnivore, using its beak to crop plants and capture small animals.

A juvenile ''Gallimimus bullatus'' skull.
In popular culture
Although ''Gallimimus'' did not appear before the Cretaceous Period, the dinosaur appeared on-screen, in the motion picture ''
Jurassic Park''. A flock of running ''Gallimimus'' was seen running across a vast field from a ''
Tyrannosaurus'', which hunted and killed one of the ornithomimids. ''Gallimimus'' is also featured in the film's first sequel, '', during the 'roundup' sequence.
References
★ Kobayashi, Y. & R. Barsbold, 2006. Ornithomimids from the Nemegt Formation of Mongolia. ''J. Paleont. Soc. Korea'' 22 (1): 195-207.