How far apart in time were famous dinosaurs?
Stegosaurus and Tyrannosaurus are separated by 72.9 million years on this site. The young end of the Stegosaurus range is 145 million years ago and the old end of the Tyrannosaurus range is 72.1. That gap is wider than the 66 million years between the last of the non-bird dinosaurs and today.
Ten famous pairs
The table measures each pair the same way. Where the ranges do not touch, the gap runs from the young end of the older genus to the old end of the younger one. Where they share stages, the overlap is the length of the shared part.
| Pair | Ranges (Ma) | Gap or overlap |
|---|---|---|
| Stegosaurus and Tyrannosaurus | 154.8–145 / 72.1–66 | 72.9 My gap |
| Allosaurus and Tyrannosaurus | 154.8–145 / 72.1–66 | 72.9 My gap |
| Brachiosaurus and Triceratops | 154.8–145 / 72.1–66 | 72.9 My gap |
| Coelophysis and Tyrannosaurus | 205.7–192.9 / 72.1–66 | 120.8 My gap |
| Plateosaurus and Stegosaurus | 205.7–201.4 / 154.8–145 | 46.6 My gap |
| Iguanodon and Tyrannosaurus | 139.8–121.4 / 72.1–66 | 49.3 My gap |
| Spinosaurus and Tyrannosaurus | 100.5–93.9 / 72.1–66 | 21.8 My gap |
| Velociraptor and Tyrannosaurus | 83.6–72.1 / 72.1–66 | meet, 0 |
| Allosaurus and Stegosaurus | 154.8–145 / 154.8–145 | 9.8 My overlap |
| Tyrannosaurus and Triceratops | 72.1–66 / 72.1–66 | 6.1 My overlap |
All ranges are stage-level fossil ranges from the Paleobiology Database, as calculated on FossilRange. My = million years.
How a gap is measured
Each end of a range is a stage boundary, so every gap and overlap on this site is measured between stage boundaries. The figure is exact only to the stage. If Stegosaurus fossils are one day dated into the earliest Cretaceous, the gap shrinks by the length of that stage. Treat a gap of a few million years as “neighbouring stages” rather than as a precise interval.
With large gaps the uncertainty hardly matters. Between Stegosaurus and Tyrannosaurus lie 11 complete stages, from the Berriasian to the Campanian. The whole of the Early Cretaceous falls in the gap.
Who lived in between
35 genera on this site have ranges that fall wholly inside the gap between Stegosaurus and Tyrannosaurus. The best-recorded of them are Iguanodon, Tenontosaurus, Psittacosaurus, Centrosaurus and Deinonychus. Among them is Spinosaurus (100.5–93.9 Ma), which is closer in time to Tyrannosaurus than to Stegosaurus: 21.8 million years from one, 44.5 from the other.
The widest gap on the site
The widest gap between any two genera here is 129.3 million years, between genera of the Rhaetian and the Maastrichtian. 13 pairs share that maximum, for example Alamosaurus and Plateosaurus. In all, 862 of the 4,851 pairs on the site are further apart than the 66 million years that separate the end of the Cretaceous from today.
Large gaps inside one period
A gap does not need to cross a period boundary to be large. Inside the Jurassic, the widest gap between two purely Jurassic genera on this site is 43.7 million years, for example between Brontosaurus (149.2–145 Ma) and Scelidosaurus (199.5–192.9 Ma). Inside the Cretaceous it is 49.3 million years, for example between Triceratops (72.1–66 Ma) and Iguanodon (139.8–121.4 Ma).
Labels such as “Jurassic dinosaur” or “Cretaceous dinosaur” therefore hide a lot. Dilophosaurus and Stegosaurus are both Jurassic, yet 29.4 million years separate them, more than the whole span of the Late Cretaceous on this time scale (34.5 million years). The stage names on each genus page are a better guide to who could have met whom than the period name.
When a pair “meets”
Velociraptor (83.6–72.1 Ma) and Tyrannosaurus (72.1–66 Ma) touch at 72.1 million years ago, the boundary between the Campanian and the Maastrichtian. On stage-level data the gap is zero and the overlap is zero. The ranges alone cannot settle whether the two lived at the same moment.
Their fossils mostly come from different places: Velociraptor from Mongolia, China, Canada and Kazakhstan, Tyrannosaurus from the United States, Canada and Mexico. The database does list 1 collection holding both names. A single record like that is worth checking in the original publication before reading much into it, because identifications in the database change as research continues.
Try other pairs
The compare tool works for any two of the 99 genera and lists how many genera lived wholly in the gap. For pairs whose ranges overlap, see Which dinosaurs lived at the same time?, which also counts the pairs found in the same fossil collections.
Sources
- The Paleobiology Database (paleobiodb.org), data service v1.2, licensed CC BY 4.0; retrieved 2026-10-27. All counts, ranges and pairs in this article are calculated by FossilRange from that download.
- International Commission on Stratigraphy, International Chronostratigraphic Chart: stage names, base ages and colours.
- FossilRange, Data & method: which genera are included and how ranges are derived.