Dinosaur genus
Alvarezsaurus
Alvarezsaurus is a dinosaur genus known from bones, found in rocks 85.7–83.6 million years old, in Argentina.
Confidence labels are switched off. Facts with low confidence, or where sources disagree, still carry a small dot: tap it for the reason.
At a glance
Data as of 12 October 2026- Named by
- Bonaparte 1991
high
high: PBDB and Wikidata agree.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Described in
- J. F. Bonaparte (1991). Los vertebrados fósiles de la Formación Rio Colorado, de la Ciudad de Neuquén y Cercanías, Cretácico Superior, Argentina [The vertebrate fossils of the Rio Colorado Formation, from the city of Neuquén and surrounding areas, Upper Cretaceous, Argentina]. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigación de las Ciencias Naturales: Paleontología 4(3): 17–123.
high
high: PBDB gives this publication for the name; its author and year match the naming authority (Bonaparte 1991), on which PBDB and Wikidata agree.Sources
Given by: Paleobiology Database. The publication the Paleobiology Database gives as the authority for this genus name, usually the one that first named and described it.
- Lived
- Santonian, 85.7–83.6 million years ago
medium
medium: Only PBDB gives this; nothing contradicts it.Omnisaura calculation85.7–83.6 million years ago, from its dated fossil recordslow
low: Omnisaura's calculation from only 1 dated record(s).Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Fossils found in
- Argentina
low
low: Only one PBDB record.Sources
Given by: Paleobiology Database. How it was chosen: Union of all sources (ISO 3166).
- Rock formations
- Bajo de la Carpa
low
low: Only one PBDB record.Sources
Given by: Paleobiology Database. How it was chosen: Canonical names, automatic and editor-approved matches applied.
- Family
- Alvarezsauridae
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Parent group
- Alvarezsauridae
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Known from
- Bones
Sources
Given by: Paleobiology Database (what the name was based on).
Gaps are answers
What isn't known yet
- Type species: no source we use gives it yet.
- Order: no source we use gives it yet.
- Common names: no source we use gives it yet.
- What it was named after: no source we use gives it yet.
- Resting on one source: 3 facts come from a single source with nothing against them (rated medium): parent group (PBDB); family (PBDB); age (headline) (PBDB).
Size, diet and behaviour aren't covered yet. Omnisaura leaves them out rather than guess.
Where sources disagree
None open. Where our sources overlap, they agree on everything shown here.
Did it meet…?
No. Alvarezsaurus had gone at least 0 million years before Tyrannosaurus appears in the fossil record.
Going by the ages and rock formations of their dated fossils, as on the map. Compare their fossil sites on the map.
Lived alongside
Genera found in the same rock formations, from rocks of the same age.
Same family
Other genera in Alvarezsauridae with a full profile.
Credits
Where this page comes from
- Paleobiology DatabaseCC BY 4.0 · fossil records, ages, classification
- WikidataCC0 1.0 · names and identifiers
- OmnisauraOmnisaura editorial · confidence levels and gaps
- PaleoMAP PaleoCoastlines (Kocsis and Scotese 2021)CC BY 4.0 · ancient coastlines on the small map
- Natural EarthPublic domain · today's coastlines
Pictures linked from this page are credited beside each one, with their own licences; the full list is in the JSON download.