Cretaceous
Troodon
Troodon formosus
The catalogue presents Troodon as a omnivore member of Troodontidae that lived during the Cretaceous, between 77.0–66.0 Ma. Its estimated range is 2.0–2.4 m in length and 40–50 kg in mass, giving a practical sense of scale. Reference material comes from Judith River Formation, Montana, USA. Size and mass are approximations and may change with new fossils or methods.
Evidence-backed summary
For Troodon, the PBDB records the taxonomic attribution as Leidy (1856).
The PBDB places it in Troodontini, and the catalogue record assigns it to the family Troodontidae.
- PBDB · taxon.parent
- Troodontidae
In the PBDB record, the reported stratigraphic range runs from the Campanian to the Maastrichtian.
The PBDB catalogues 55 occurrences, with material from the Dinosaur Park Formation (15), from the Oldman Formation (13) and from the Judith River Formation (9). Provenance: Canada, United States and Russia.
The catalogue records the holotype as NMC 8539 and the type locality as “Judith River Formation, Montana, USA”.
- NMC 8539
- Judith River Formation, Montana, USA
The catalogue's reference measurements are 2.0–2.4 m in length and 40–50 kg in mass — estimates, which vary with specimen and method.
- 2.0-2.4 m
- 40-50 kg
The record gathers 128 bibliographic references registered in the PBDB, listed below.
Where it lived
Fossil occurrences on today’s map and in the tectonic reconstruction.
Positions reconstructed by PBDB/GPlates, not observed; this is not an exact habitat map.
Artistic 3D reconstruction
There is no approved species-specific 3D model yet. Generic anatomy will not be presented as if it were evidence.
Physical Specifications
- Length
- 2.0–2.4 m
- Weight
- 40–50 kg
- Period
- Cretaceous
- Time range
- 77.0–66.0 Ma
Discovery Information
- First Discovery
- 1856
- Described by
- Joseph Leidy
Taxonomic Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Reptilia
- Order
- Saurischia
- Family
- Troodontidae
- Genus
- Troodon
- Species
- T. formosus
Data status
Taxonomic name matched to PBDB and checked on 2026-08-08.
Taxonomic linkage does not automatically validate size, mass, behaviour or appearance.
- Type specimen
- NMC 8539
- Type locality
- Judith River Formation, Montana, USA