Egg type
Montanoolithus
Montanoolithus is an egg type: the name is for the fossil eggs themselves. The animal that laid them is not known for certain. Its eggs are found in rocks 83.6–66 million years old in Canada, France and the United States.
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
- Zelenitsky and Therrien 2008
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Described in
- D. K. Zelenitsky, F. Therrien (2008). Unique maniraptoran egg clutch from the Upper Cretaceous Two Medicine Formation of Montana reveals theropod nesting behaviour. Palaeontology 51(6): 1253–1259. Read it
medium
medium: Only PBDB gives this; its author and year match the naming authority (Zelenitsky and Therrien 2008).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.
- Dated to
- Campanian to Maastrichtian, 83.6–66 million years ago
medium
medium: Only PBDB gives this; nothing contradicts it.Omnisaura calculation83.6–66 million years ago, from its dated fossil recordsmedium
medium: Omnisaura's calculation from 4 confirmed PBDB records.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Found in
- CanadaFrance
medium
medium: Only PBDB records it (2 records).United Stateslow
low: Only one PBDB record.low
low: Only one PBDB record.mixed
mixed: Levels differ between entries; each has its own.Sources
Given by: Paleobiology Database. How it was chosen: Union of all sources (ISO 3166).
- Rock formations
- OldmanMarnes Rouges Inférieures
medium
medium: Only PBDB records it (2 records).Two Medicinelow
low: Only one PBDB record.low
low: Only one PBDB record.mixed
mixed: Levels differ between entries; each has its own.Sources
Given by: Paleobiology Database. How it was chosen: Canonical names, automatic and editor-approved matches applied.
- Egg family
- Montanoolithidae
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Parent group
- Montanoolithidae
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Known from
- Eggs
Sources
Given by: Paleobiology Database (what the name was based on).
- Laid by
- Not known for certain. Eggs rarely show which animal laid them.
Gaps are answers
What isn't known yet
- The animal that laid them: not known for certain, as for most egg types.
- 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: 4 facts come from a single source with nothing against them (rated medium): authority (PBDB); 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…?
Same time, different places. Their fossils overlap in age, 83.6 to 66 million years ago, but no rock formation holds both.
Going by the ages and rock formations of their dated fossils, as on the map. Compare their fossil sites on the map.
Found in the same rocks
Genera and other fossil types from the same formations, from rocks of the same age.
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