Egg type

Tristraguloolithus

Zelenitsky et al. 1996

Tristraguloolithus 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 83.6–72.2 million years old in Canada.

Confidence labels

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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 11 October 2026

83.6–72.2 Ma

Triassic

Jurassic

Cretaceous

252 million years ago20114366

The last non-bird dinosaurs died out 66 million years ago. That's as far from us as the end of this bar.

Named by: Zelenitsky et al. 1996
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, L. V. Hills, P. J. Currie (1996). Parataxonomic classification of ornithoid eggshell fragments from the Oldman Formation (Judith River Group; Upper Cretaceous), southern Alberta. Canadian Journal of Earth Sciences 33: 1655–1667. Read it
medium
medium: Only PBDB gives this; its author and year match the naming authority (Zelenitsky et al. 1996).
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.
Type species: Tristraguloolithus cracioides
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Dated to: Campanian, 83.6–72.2 million years ago
medium
medium: Only PBDB gives this; nothing contradicts it.
Omnisaura calculation83.6–72.2 million years ago, from its dated fossil records
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medium: Omnisaura's calculation from 3 confirmed PBDB records.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Found in: Canada
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medium: Only PBDB records it (3 records).
Sources
Given by: Paleobiology Database. How it was chosen: Union of all sources (ISO 3166).
Rock formations: Oldman
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medium: Only PBDB records it (3 records).
Sources
Given by: Paleobiology Database. How it was chosen: Canonical names, automatic and editor-approved matches applied.
Parent group: Theropoda
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Species named in its records: Tristraguloolithus cracioides
Sources
Given by: Paleobiology Database (the species its fossil records are identified as).
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.

Sources: Paleobiology Database (CC BY 4.0), Wikidata (CC0 1.0)Confidence levels and gaps are Omnisaura's own assessment.

Gaps are answers

What isn't known yet

The animal that laid them: not known for certain, as for most egg types.
Order: no source we use gives it yet.
Family: 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.
Held back: 1 fossil record left out: identified only tentatively (for example "cf.", "?" or the name in quotation marks).
Resting on one source: 4 facts come from a single source with nothing against them (rated medium): authority (PBDB); type species (PBDB); parent group (PBDB); age (headline) (PBDB).

Size and appearance aren't covered yet, and diet and way of life only as PBDB infers them for the wider group. Omnisaura leaves the rest out rather than guess.

Where sources disagree

None open. Where our sources overlap, they agree on everything shown here.

Did it meet…?

Did Tristraguloolithus meet ?

Same time, different places. Their fossils overlap in age, 83.6 to 72.2 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.

Connections

Genera linked to Tristraguloolithus by where and when their fossils were found, by classification and by who named them. Select a name to open its page.

Found in the same rocks 38

Genera and other fossil types from the same rock units, from rocks of overlapping age, the most shared fossil sites first.

Saurornitholestes Troodon Richardoestesia Paronychodon Dromaeosaurus Daspletosaurus Stenonychosaurus Struthiomimus Centrosaurus Monoclonius Continuoolithus Porituberoolithus Spheroolithus Brachylophosaurus Coronosaurus Corythosaurusand 22 more

Same parent group: Theropoda 33

Other genera in Theropoda with a full profile.

Ageroolithus Anteavis Boutakioutichnium Byakudansauropus Carmelopodus Corpulentapus Dispersituberoolithus Eutynichnium Gypsichnites Hadrosaurichnus Hispanosauropus Iberosauripus Irenesauripus Jialingpus Kalohipus Kayentapusand 17 more

Named by Zelenitsky 6

Genera whose naming authority includes the same surname. The authority has no initials, so different people who share a surname can appear together.

Continuoolithus Dispersituberoolithus Montanoolithus Porituberoolithus Preprismatoolithus Reticuloolithus

Found in Canada 73

Other genera found in Canada, from rocks of overlapping age, the most fossil sites there first.

Saurornitholestes Richardoestesia Centrosaurus Troodon Paronychodon Dromaeosaurus Corythosaurus Chasmosaurus Lambeosaurus Stegoceras Gorgosaurus Prosaurolophus Stenonychosaurus Euoplocephalus Styracosaurus Daspletosaurusand 57 more

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