Omnisaura
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Egg type

Undulatoolithus

Wang et al. 2013

Undulatoolithus 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 100.5–66 million years old in China and the United States.

Confidence labels
How sure are we?0 high6 medium5 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 12 October 2026
100.5–66 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
Wang et al. 2013
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

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

Described in
Q. Wang, Z. Zhao, X. Wang, N. Li, S. Zou (2013). A new form of Elongatoolithidae, Undulatoolithus pengi oogen. et oosp. nov. from Pingxiang, Jiangxi, China. Zootaxa 3746(1): 194–200. Read it
mediummedium: Only PBDB gives this; its author and year match the naming authority (Wang et al. 2013).
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
Undulatoolithus pengi
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

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

Dated to
Cenomanian, 100.5–93.9 million years ago
mediummedium: Only PBDB gives this; nothing contradicts it.
Omnisaura calculation100.5–66 million years ago, from its dated fossil records
lowlow: Omnisaura's calculation from only 2 dated record(s).
Sources

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

Found in
China
lowlow: Only one PBDB record.
United States
lowlow: Only one PBDB record.
Sources

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

Rock formations
Cedar Mountain
lowlow: Only one PBDB record.
Zhoutian
lowlow: Only one PBDB record.
Sources

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

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

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

Parent group
Elongatoolithidae
mediummedium: 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.
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.
  • 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: 5 facts come from a single source with nothing against them (rated medium): authority (PBDB); type species (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.

MacroelongatoolithusEolambiaContinuoolithusFonaSpheroolithusParonychodonRichardoestesiaAbydosaurusParafaveoloolithus

Same family

Other genera in Elongatoolithidae with a full profile.

ContinuoolithusElongatoolithusMacroelongatoolithusMacroolithusNanhsiungoolithusPorituberoolithusTrachoolithus

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