Chasmosaurus
Named by Lambe 1914 · Ceratopsidae · Horned dinosaurs
Lived 83.6–72.1 million years ago, in the Campanian stage of the Late Cretaceous.Below: the genera most often found in the same fossil collections, on the same time scale.
Top: the whole age of dinosaurs, 251.9–66 million years ago; the outlined part is enlarged below. Each bar spans the ICS stages its well-dated fossil records fall in.
Chasmosaurus lived 83.6–72.1 million years ago, during the Campanian stage of the Late Cretaceous. The Paleobiology Database lists 21 fossil records for it from 2 countries (Canada and United States) — the 59th most of the 99 genera on this site.
Most of what is known comes from one rock unit: 86% of its records are from the Dinosaur Park Formation.
Troodon appears in 10% of the collections that hold Chasmosaurus; Citipes in 5%.
Its stage range spans about 11.5 million years (the 35th longest of 99); it is the 5th best-recorded of the 11 horned dinosaurs here.
- Lived
- 83.6–72.1 Ma
- Stage
- Campanian
- Period
- Cretaceous
- Group
- Horned dinosaurs
- Family
- Ceratopsidae
- Fossil records
- 21 · #59 of 99
- Collections
- 21
- Countries
- 2
How it compares with the other 98
Each thin line is one genus on this site — darker where several share a value. The marked line is Chasmosaurus.
Fossil records
21
59th most of 99 genera
Countries with records
2
Shared with 39 other genera
Length of stage range
11.5 My
35th longest of 99 genera
Where its fossils were found
21 fossil records with coordinates, at present-day positions.
States and provinces
Countries
The rocks it comes from, and the company it kept
Share of its 21 fossil records by rock formation; then the genera most often dug up in the same collections.
- Dinosaur Park 18 · 86%
- Oldman 1 · 5%
- Judith River 1 · 5%
- Other or unnamed formations 1 · 5%
2 accepted species
- Chasmosaurus belliLambe 1902 · 7 records
- Chasmosaurus russelliSternberg 1940 · 4 records
Where it was buried
Depositional setting of its fossil sites, where known
- Channel6
- Channel lag3
- Fine channel fill1
- Crevasse splay1
Other horned dinosaurs of its time
Same group, overlapping stage range, never found in the same collections. The amber band marks when Chasmosaurus lived.
- Protoceratops83.6–72.1 MaMongolia, China
- Bagaceratops83.6–72.1 MaMongolia, China
- Agujaceratops83.6–72.1 MaUnited States, Mexico
- Pachyrhinosaurus83.6–66 MaCanada, United States
- Pentaceratops83.6–72.1 MaUnited States
- Monoclonius83.6–72.1 MaUnited States, Canada
Also from the same formations
Data: Paleobiology Database, taxon 38855 (CC BY 4.0), retrieved 2026-10-27. Ages follow the ICS chart — see how ranges are worked out.