ZPAL MgD-I/1 cast mount
Gallimimus bullatus • “Chicken mimic with capsule”
A fleet-footed ostrich-mimic theropod with a toothless keratinous beak suited for omnivorous grazing on vegetation, seeds, and small wetland invertebrates.
Ghost Ranch quarry skeleton mount
Coelophysis bauri • “Hollow form”
A gracile, agile early theropod that flourished across Late Triassic floodplains, hunting small vertebrates and insects with slender grasping jaws and lightweight hollow bones.
Gallimimus bullatus lived during the Cretaceous, while Coelophysis bauri inhabited the Triassic. They were separated by roughly 130 million years of deep time and never encountered one another in the ancient world. Gallimimus bullatus was an adapted omnivore, whereas Coelophysis bauri was a carnivore, representing fundamentally distinct ecological roles. Based on available fossil estimates, Gallimimus bullatus was larger than Coelophysis bauri in both overall length and estimated body mass (approximately 18× heavier and 2× longer). Estimates vary between individual specimens.
Anatomical dimensions compared on a shared proportional baseline against an adult human (1.8 m / 5.9 ft).
Gallimimus bullatus was longer by approximately 3 m.
Gallimimus bullatus stood taller by approximately 1 m.
Gallimimus bullatus had a greater estimated mass by 0.4 tonnes.
Based on available fossil estimates, Gallimimus bullatus was larger than Coelophysis bauri in both overall length and estimated body mass (approximately 18× heavier and 2× longer). Estimates vary between individual specimens.
Paleontological Note on Mass Estimates: Dinosaur body weights are derived through volumetric laser scanning and femoral circumference scaling equations. Because soft tissue does not fossilize directly, mass values carry statistical margins of uncertainty and represent scientific estimates rather than exact weights.
Direct answers to the most important comparative questions about how these two prehistoric species differed.
Based on available fossil estimates, Gallimimus bullatus was larger than Coelophysis bauri in both overall length and estimated body mass (approximately 18× heavier and 2× longer). Estimates vary between individual specimens.
Gallimimus bullatus was an adapted omnivore, whereas Coelophysis bauri was a carnivore, representing fundamentally distinct ecological roles.
Gallimimus bullatus lived during the Cretaceous (Late Cretaceous, 70 Ma), while Coelophysis bauri lived during the Triassic (Late Triassic, 228–201 Ma).
Fossils of Gallimimus bullatus were recovered from Mongolia (Nemegt Basin), whereas Coelophysis bauri was discovered in New Mexico, Arizona (Ghost Ranch).
Gallimimus bullatus had a bipedal locomotion, contrasted with Coelophysis bauri which had a bipedal stance.
Gallimimus bullatus and Coelophysis bauri did NOT live at the same time. They were separated by an immense temporal gulf of approximately 130 million years. Coelophysis bauri lived and went extinct tens of millions of years before Gallimimus bullatus ever evolved.
Side-by-side catalog of verified anatomical measurements and geological records.
| Scientific Parameter | A Gallimimus bullatus | B Coelophysis bauri |
|---|---|---|
| Scientific Binomial | Gallimimus bullatus | Coelophysis bauri |
| Name Meaning | “Chicken mimic with capsule” | “Hollow form” |
| Taxonomic Clade / Group | Theropods | Theropods |
| Geological Period | Cretaceous | Triassic |
| Fossil Time Range | Late Cretaceous, 70 Ma | Late Triassic, 228–201 Ma |
| Diet & Trophic Guild | Omnivore | Carnivore |
| Maximum Length | 6 m (19.7 ft) | 3 m (9.8 ft) |
| Standing / Hip Height | 2 m (6.6 ft) | 1 m (3.3 ft) |
| Estimated Body Mass | 0.5 tonnes (450 kg) | 0 tonnes (25 kg) |
| Locomotion / Stance | Bipedal | Bipedal |
| Geographic Localities | Mongolia (Nemegt Basin) | New Mexico, Arizona (Ghost Ranch) |
| Geological Formation | Nemegt Formation | Chinle Formation |
| Discovery History | Historical holotype | Historical holotype |
Visualizing both species across the 186-million-year span of the Mesozoic Era.
Gallimimus bullatus and Coelophysis bauri did NOT live at the same time. They were separated by an immense temporal gulf of approximately 130 million years. Coelophysis bauri lived and went extinct tens of millions of years before Gallimimus bullatus ever evolved.
Deep-time perspective: Gallimimus bullatus and Coelophysis bauri were separated by approximately 130 million years. A visitor encountering one would have had no concept of the other.
Comparing the rock strata, paleoclimates, and ancient landscapes where their fossils were entombed.
Mongolia (Nemegt Basin)
Asia
New Mexico, Arizona (Ghost Ranch)
North America
Stratigraphic Synthesis:
Direct comparisons between extinct animals are inherently shaped by the incomplete nature of the fossil record. Skeletal dimensions reflect holotype or well-preserved paratype specimens, but individual ontogenetic age, sexual dimorphism, and intraspecific variation all influence the true living size of any prehistoric animal.
Body mass estimates shown above represent calculated averages from published volumetric models and biomechanical limb scaling. As modern synchrotron imaging and 3D digital skeletal mounts advance, museum measurements are continually refined.