Omnisaura

Egg type

Preprismatoolithus

Zelenitsky and Hills 1996

Preprismatoolithus 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 154.8–143.1 million years old in the United States.

Confidence labels
How sure are we?0 high8 medium0 lowHow we rate confidence

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
154.8–143.1 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 and Hills 1996
mediummedium: 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 (1996). An egg clutch of Prismatooiitlbus levis oosp. nov. from the Oldman Formation (Upper Cretaceous) Devil's Coulee, southern Alberta. Canadian Journal of Earth Sciences 33: 1127–1131. Read it
mediummedium: Only PBDB gives this; its author and year match the naming authority (Zelenitsky and Hills 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.

Dated to
Kimmeridgian to Tithonian, 154.8–143.1 million years ago
mediummedium: Only PBDB gives this; nothing contradicts it.
Omnisaura calculation154.8–143.1 million years ago, from its dated fossil records
mediummedium: Omnisaura's calculation from 7 confirmed PBDB records.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Found in
United States
mediummedium: Only PBDB records it (7 records).
Sources

Given by: Paleobiology Database. How it was chosen: Union of all sources (ISO 3166).

Rock formations
Morrison Formation
mediummedium: Only PBDB records it (7 records).
Sources

Given by: Paleobiology Database. How it was chosen: Canonical names, automatic and editor-approved matches applied.

Egg family
Prismatoolithidae
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Parent group
Prismatoolithidae
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Older or other names
Prismatoolithus (a name it replaced)
Sources

Given by: Paleobiology Database (names it treats as this genus).

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), Natural History Museum Data Portal (CC0 1.0), 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.
  • 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 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…?

?

No. Preprismatoolithus had gone at least 59.5 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.

Connections

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

PreprismatoolithusFound in the same rocksSame familySame naming authorAlso found in United StatesAllosaurusCamarasaurusStegosaurusDiplodocusand 30 morePrismatoolithusProtoceratopsidovumSankofaSpheruprismatoolithusContinuoolithusDispersituberoolithusMontanoolithusPorituberoolithusand 2 moreApatosaurusCamptosaurusDryosaurusNanosaurusand 34 more

Found in the same rocks 34

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

AllosaurusCamarasaurusStegosaurusDiplodocusApatosaurusCamptosaurusDryosaurusNanosaurusBrontosaurusCeratosaurusBarosaurusBrachiosaurusTorvosaurusHesperosaurusCoelurusHaplocanthosaurusand 18 more

Same family: Prismatoolithidae 4

Other genera in Prismatoolithidae with a full profile.

PrismatoolithusProtoceratopsidovumSankofaSpheruprismatoolithus

Named by Hills and 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.

ContinuoolithusDispersituberoolithusMontanoolithusPorituberoolithusReticuloolithusTristraguloolithus

Found in United States 38

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

AllosaurusCamarasaurusStegosaurusDiplodocusApatosaurusCamptosaurusDryosaurusNanosaurusBrontosaurusCeratosaurusBarosaurusBrachiosaurusTorvosaurusHesperosaurusCoelurusHaplocanthosaurusand 22 more

Credits

Where this page comes from

  • Paleobiology DatabaseCC BY 4.0 · fossil records, ages, classification
  • Natural History Museum Data PortalCC0 1.0 · catalogued specimens
  • 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