FMNH PR 2081 ("Sue")
Tyrannosaurus rex • “Tyrant Lizard King”
Tyrannosaurus rex was one of the largest terrestrial carnivores of all time, roaming western North America just prior to the Cretaceous-Paleogene extinction event. With…
MSNM V4047 / FSAC-KK 11888 digital skeletal cast mount
Spinosaurus aegyptiacus • “Spine lizard of Egypt”
A colossal semi-aquatic predatory theropod equipped with a massive dorsal neural sail, crocodyliform snout, and paddle-like tail adapted for pursuing giant Cretaceous fish.
Tyrannosaurus rex and Spinosaurus aegyptiacus were both Cretaceous dinosaurs. They were separated by roughly 25 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. Spinosaurus aegyptiacus reached greater total length from snout to tail, but Tyrannosaurus rex had a stockier, more robust build with higher estimated body mass.
Anatomical dimensions compared on a shared proportional baseline against an adult human (1.8 m / 5.9 ft).
Spinosaurus aegyptiacus was longer by approximately 2.7 m.
Spinosaurus aegyptiacus stood taller by approximately 0.8 m.
Tyrannosaurus rex had a greater estimated mass by 0.9 tonnes.
Spinosaurus aegyptiacus reached greater total length from snout to tail, but Tyrannosaurus rex had a stockier, more robust build with higher estimated body mass.
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.
Spinosaurus aegyptiacus reached greater total length from snout to tail, but Tyrannosaurus rex had a stockier, more robust build with higher estimated body mass.
Both species shared a carnivore diet, occupying comparable trophic levels in their respective food webs.
Tyrannosaurus rex lived during the Cretaceous (Late Cretaceous, 68–66 Ma), while Spinosaurus aegyptiacus lived during the Cretaceous (Late Cretaceous, 99–93 Ma).
Fossils of Tyrannosaurus rex were recovered from Western North America (Montana, South Dakota, Wyoming, Alberta, Saskatchewan), whereas Spinosaurus aegyptiacus was discovered in Egypt, Morocco (Kem Kem Beds).
Tyrannosaurus rex had a bipedal locomotion, contrasted with Spinosaurus aegyptiacus which had a bipedal / semi-aquatic stance.
Tyrannosaurus rex and Spinosaurus aegyptiacus did NOT live at the same time. They were separated by an immense temporal gulf of approximately 25 million years. Spinosaurus aegyptiacus lived and went extinct tens of millions of years before Tyrannosaurus rex ever evolved.
Side-by-side catalog of verified anatomical measurements and geological records.
| Scientific Parameter | A Tyrannosaurus rex | B Spinosaurus aegyptiacus |
|---|---|---|
| Scientific Binomial | Tyrannosaurus rex | Spinosaurus aegyptiacus |
| Name Meaning | “Tyrant Lizard King” | “Spine lizard of Egypt” |
| Taxonomic Clade / Group | Theropods | Theropods |
| Geological Period | Cretaceous | Cretaceous |
| Fossil Time Range | Late Cretaceous, 68–66 Ma | Late Cretaceous, 99–93 Ma |
| Diet & Trophic Guild | Carnivore | Carnivore |
| Maximum Length | 12.3 m (40.4 ft) | 15 m (49.2 ft) |
| Standing / Hip Height | 3.7 m (12.1 ft) | 4.5 m (14.8 ft) |
| Estimated Body Mass | 8.4 tonnes (8,400 kg) | 7.5 tonnes (7,500 kg) |
| Locomotion / Stance | Bipedal | Bipedal / Semi-aquatic |
| Geographic Localities | Western North America (Montana, South Dakota, Wyoming, Alberta, Saskatchewan) | Egypt, Morocco (Kem Kem Beds) |
| Geological Formation | Hell Creek Formation, Lance Formation, Scollard Formation | Bahariya Formation, Kem Kem Beds |
| Discovery History | Barnum Brown (1902); described by Henry Fairfield Osborn (1905) (1902) | Historical holotype |
Visualizing both species across the 186-million-year span of the Mesozoic Era.
Tyrannosaurus rex and Spinosaurus aegyptiacus did NOT live at the same time. They were separated by an immense temporal gulf of approximately 25 million years. Spinosaurus aegyptiacus lived and went extinct tens of millions of years before Tyrannosaurus rex ever evolved.
Deep-time perspective: Tyrannosaurus rex and Spinosaurus aegyptiacus were separated by approximately 25 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.
Western North America (Montana, South Dakota, Wyoming, Alberta, Saskatchewan)
North America
Egypt, Morocco (Kem Kem Beds)
Africa
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.