Cretaceous
Sphaerotholus
Sphaerotholus buchholtzae
The catalogue presents Sphaerotholus as a herbivore member of Pachycephalosauridae that lived during the Cretaceous, between 77.0–66.0 Ma. Its estimated range is 2.0–3.0 m in length and 50–100 kg in mass, giving a practical sense of scale. Reference material comes from Kirtland Formation, New Mexico, USA. Size and mass are approximations and may change with new fossils or methods.
Evidence-backed summary
For Sphaerotholus, the PBDB records the taxonomic attribution as Williamson and Carr (2003).
The PBDB places it in Pachycephalosaurinae, 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 2 occurrences, with material from the Hell Creek Formation (1) and from the Frenchman Formation (1). Provenance: United States and Canada.
The catalogue records the holotype as NMMNH P-27403 and the type locality as “Kirtland Formation, New Mexico, USA”.
- NMMNH P-27403
- Kirtland Formation, New Mexico, USA
The catalogue's reference measurements are 2.0–3.0 m in length and 50–100 kg in mass — estimates, which vary with specimen and method.
- 2.0-3.0 m
- 50-100 kg
The record gathers 10 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
- 50–100 kg
- Period
- Cretaceous
- Time range
- 77.0–66.0 Ma
Discovery Information
- First Discovery
- 2003
- Described by
- Williamson & Carr
Taxonomic Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Reptilia
- Order
- Ornithischia
- Family
- Pachycephalosauridae
- Genus
- Sphaerotholus
- Species
- S. buchholtzae
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
- NMMNH P-27403
- Type locality
- Kirtland Formation, New Mexico, USA