Cretaceous
Stygimoloch
Stygimoloch spinifer
The catalogue presents Stygimoloch as a herbivore member of Pachycephalosauridae that lived during the Cretaceous, between 68.0–66.0 Ma. Its estimated range is 2.0–3.0 m in length and 40–78 kg in mass, giving a practical sense of scale. Reference material comes from Hell Creek Formation, Montana, USA. Size and mass are approximations and may change with new fossils or methods.
Evidence-backed summary
For Stygimoloch, the PBDB records the taxonomic attribution as Galton and Sues (1983).
The PBDB places it in Eupachycephalosauria, and the catalogue record assigns it to the family Pachycephalosauridae.
- PBDB · taxon.parent
- Pachycephalosauridae
In the PBDB record, the reported stratigraphic range runs from the Campanian to the Maastrichtian.
The PBDB catalogues 7 occurrences, with material from the Hell Creek Formation (6) and from the Ferris Formation (1). Provenance: United States.
The catalogue records the holotype as UCMP 119433 and the type locality as “Hell Creek Formation, Montana, USA”.
- UCMP 119433
- Hell Creek Formation, Montana, USA
The catalogue's reference measurements are 2.0–3.0 m in length and 40–78 kg in mass — estimates, which vary with specimen and method.
- 2.0-3.0 m
- 40-78 kg
The record gathers 19 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
- 2.0–3.0 m
- Weight
- 40–78 kg
- Period
- Cretaceous
- Time range
- 68.0–66.0 Ma
Discovery Information
- First Discovery
- 1983
- Described by
- Galton & Sues
Taxonomic Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Reptilia
- Order
- Ornithischia
- Family
- Pachycephalosauridae
- Genus
- Stygimoloch
- Species
- S. spinifer
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
- UCMP 119433
- Type locality
- Hell Creek Formation, Montana, USA