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.
CMC VP 7180 mount
Allosaurus fragilis • “Different lizard, fragile”
The most common and lethal apex predator of the Late Jurassic Morrison Formation, hunting with gaping jaws, slashing bites, and robust three-clawed forelimbs.
Coelophysis bauri lived during the Triassic, while Allosaurus fragilis inhabited the Jurassic. They were separated by roughly 46 million years of deep time and never encountered one another in the ancient world. Both species shared a carnivore diet, occupying comparable trophic levels in their respective food webs. Based on available fossil estimates, Allosaurus fragilis was larger than Coelophysis bauri in both overall length and estimated body mass (approximately 80× heavier and 2.83× longer). Estimates vary between individual specimens.
Anatomical dimensions compared on a shared proportional baseline against an adult human (1.8 m / 5.9 ft).
Allosaurus fragilis was longer by approximately 5.5 m.
Allosaurus fragilis stood taller by approximately 2 m.
Allosaurus fragilis had a greater estimated mass by 2 tonnes.
Based on available fossil estimates, Allosaurus fragilis was larger than Coelophysis bauri in both overall length and estimated body mass (approximately 80× heavier and 2.83× 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, Allosaurus fragilis was larger than Coelophysis bauri in both overall length and estimated body mass (approximately 80× heavier and 2.83× longer). Estimates vary between individual specimens.
Both species shared a carnivore diet, occupying comparable trophic levels in their respective food webs.
Coelophysis bauri lived during the Triassic (Late Triassic, 228–201 Ma), while Allosaurus fragilis lived during the Jurassic (Late Jurassic, 155–145 Ma).
Fossils of Coelophysis bauri were recovered from New Mexico, Arizona (Ghost Ranch), whereas Allosaurus fragilis was discovered in Western United States (Morrison Formation), Portugal.
Coelophysis bauri had a bipedal locomotion, contrasted with Allosaurus fragilis which had a bipedal stance.
Coelophysis bauri and Allosaurus fragilis did NOT live at the same time. They were separated by an immense temporal gulf of approximately 46 million years. Coelophysis bauri lived and went extinct tens of millions of years before Allosaurus fragilis ever evolved.
Side-by-side catalog of verified anatomical measurements and geological records.
| Scientific Parameter | A Coelophysis bauri | B Allosaurus fragilis |
|---|---|---|
| Scientific Binomial | Coelophysis bauri | Allosaurus fragilis |
| Name Meaning | “Hollow form” | “Different lizard, fragile” |
| Taxonomic Clade / Group | Theropods | Theropods |
| Geological Period | Triassic | Jurassic |
| Fossil Time Range | Late Triassic, 228–201 Ma | Late Jurassic, 155–145 Ma |
| Diet & Trophic Guild | Carnivore | Carnivore |
| Maximum Length | 3 m (9.8 ft) | 8.5 m (27.9 ft) |
| Standing / Hip Height | 1 m (3.3 ft) | 3 m (9.8 ft) |
| Estimated Body Mass | 0 tonnes (25 kg) | 2 tonnes (2,000 kg) |
| Locomotion / Stance | Bipedal | Bipedal |
| Geographic Localities | New Mexico, Arizona (Ghost Ranch) | Western United States (Morrison Formation), Portugal |
| Geological Formation | Chinle Formation | Morrison Formation, Lourinhã Formation |
| Discovery History | Historical holotype | Historical holotype |
Visualizing both species across the 186-million-year span of the Mesozoic Era.
Coelophysis bauri and Allosaurus fragilis did NOT live at the same time. They were separated by an immense temporal gulf of approximately 46 million years. Coelophysis bauri lived and went extinct tens of millions of years before Allosaurus fragilis ever evolved.
Deep-time perspective: Coelophysis bauri and Allosaurus fragilis were separated by approximately 46 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.
New Mexico, Arizona (Ghost Ranch)
North America
Western United States (Morrison Formation), Portugal
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.