Cretaceous
Orodromeus
Orodromeus makelai
The catalogue presents Orodromeus as a herbivore member of Thescelosauridae that lived during the Cretaceous, between 77.5–74.0 Ma. Its estimated range is 2.5 m in length and 40–50 kg in mass, giving a practical sense of scale. Reference material comes from Two Medicine Formation, Montana, USA. Size and mass are approximations and may change with new fossils or methods.
Evidence-backed summary
For Orodromeus, the PBDB records the taxonomic attribution as Horner and Weishampel (1988).
The PBDB places it in Orodrominae, and the catalogue record assigns it to the family Thescelosauridae.
- PBDB · taxon.parent
- Thescelosauridae
In the PBDB record, the reported stratigraphic range runs from the Campanian to the Maastrichtian.
The PBDB catalogues 8 occurrences, with material from the Two Medicine Formation (6), from the Hell Creek Formation (1) and from the Judith River Formation (1). Provenance: United States.
The catalogue records the holotype as MOR 294 and the type locality as “Two Medicine Formation, Montana, USA”.
- MOR 294
- Two Medicine Formation, Montana, USA
The catalogue's reference measurements are 2.5 m in length and 40–50 kg in mass — estimates, which vary with specimen and method.
- 2.5 m
- 40-50 kg
The record gathers 26 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
- 2.5 m
- Weight
- 40–50 kg
- Period
- Cretaceous
- Time range
- 77.5–74.0 Ma
Discovery Information
- First Discovery
- 1988
- Described by
- Horner & Weishampel
Taxonomic Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Reptilia
- Order
- Ornithischia
- Family
- Thescelosauridae
- Genus
- Orodromeus
- Species
- O. makelai
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
- MOR 294
- Type locality
- Two Medicine Formation, Montana, USA