Cretaceous
Alvarezsaurus
Alvarezsaurus calvoi
The catalogue presents Alvarezsaurus as a carnivore member of Alvarezsauridae that lived during the Cretaceous, between 85.7–83.6 Ma. Its estimated range is 1.8–2.5 m in length and 8–15 kg in mass, giving a practical sense of scale. Reference material comes from Bajo de la Carpa Formation, Neuquén, Argentina. Size and mass are approximations and may change with new fossils or methods.
Evidence-backed summary
For Alvarezsaurus, the PBDB records the taxonomic attribution as Bonaparte (1991).
The PBDB places it in Alvarezsauridae, and the catalogue record assigns it to the family Alvarezsauridae.
- PBDB · taxon.parent
- Alvarezsauridae
In the PBDB record, the reported stratigraphic range is the Santonian.
The PBDB catalogues 1 occurrence, with material from the Bajo de la Carpa Formation (1). Provenance: Argentina.
The catalogue records the holotype as MUCPv-54 and the type locality as “Bajo de la Carpa Formation, Neuquén, Argentina”.
- MUCPv-54
- Bajo de la Carpa Formation, Neuquén, Argentina
The catalogue's reference measurements are 1.8–2.5 m in length and 8–15 kg in mass — estimates, which vary with specimen and method.
- 1.8-2.5 m
- 8-15 kg
The record gathers 25 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
- 1.8–2.5 m
- Weight
- 8–15 kg
- Period
- Cretaceous
- Time range
- 85.7–83.6 Ma
Discovery Information
- First Discovery
- 1991
- Described by
- José Bonaparte
Taxonomic Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Reptilia
- Order
- Saurischia
- Family
- Alvarezsauridae
- Genus
- Alvarezsaurus
- Species
- c. calvoi
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
- MUCPv-54
- Type locality
- Bajo de la Carpa Formation, Neuquén, Argentina