Egg type

Macroolithus

Zhao 1975

Macroolithus 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 4 countries, most often China and Mongolia.

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 12 October 2026

100.5–66 Ma

Triassic

Jurassic

Cretaceous

252 million years ago20114366

Solid: the ages of its dated fossils, 100.5–66 million years ago (Omnisaura's calculation). Pale: the published range, 132.6–66 million years ago, which also counts records Omnisaura leaves out.

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: Zhao 1975
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Described in: Z.-K. Zhao (1975). [The microstructures of the dinosaurian eggshells of Nanxiong Basin, Guandong province. (1) On the classification of dinosaur eggs]. Vertebrata PalAsiatica 13(2): 105–117.
medium
medium: Only PBDB gives this; its author and year match the naming authority (Zhao 1975).
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: Macroolithus rugustus
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Dated to: Hauterivian to Maastrichtian, 132.6–66 million years ago
medium
medium: Only PBDB gives this; nothing contradicts it.
Omnisaura calculation100.5–66 million years ago, from its dated fossil records
medium
medium: Omnisaura's calculation from 49 confirmed PBDB records.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Found in: China
medium
medium: Only PBDB records it (42 records).
Mongolia
medium
medium: Only PBDB records it (6 records).
Kazakhstan
low
low: Only one PBDB record.
Spain
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: Nemegt
medium
medium: Only PBDB records it (4 records).
Pingling
medium
medium: Only PBDB records it (14 records).
Yuanpu
medium
medium: Only PBDB records it (6 records).
Zhenshui
medium
medium: Only PBDB records it (7 records).
Zhutian
medium
medium: Only PBDB records it (9 records).
Baruungoyot
low
low: Only one PBDB record.
Djadokhta
low
low: Only one PBDB record.
Dongyuan
low
low: Only one PBDB record.
El Castellar
low
low: Only one PBDB record.
Hekou
low
low: Only one PBDB record.
Nanchao
low
low: Only one PBDB record.
Tayzhuzgen
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: Elongatoolithidae
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Parent group: Elongatoolithidae
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.

Sources: Omnisaura editorial (Omnisaura editorial content (© Future Sailors, all rights reserved)), 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.
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.
Held back: 1 fossil record left out: identified only tentatively (for example "cf." or "?").
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…?

Did Macroolithus 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.

Tarbosaurus Elongatoolithus Saurolophus Gallimimus Protoceratops Bagaceratops Velociraptor Pinacosaurus Protoceratopsidovum Avimimus Coralloidoolithus Dendroolithus Faveoloolithus Nanhsiungoolithus Shixingoolithus Spheroolithusand 43 more

Same family

Other genera in Elongatoolithidae with a full profile.

Continuoolithus Elongatoolithus Macroelongatoolithus Nanhsiungoolithus Porituberoolithus Trachoolithus Undulatoolithus

Where its fossils were found

22 fossil sites, with present-day and ancient positions

Open the map at this time

Cite this page

Omnisaura (2026). Macroolithus. Future Sailors. https://www.omnisaura.com/genera/macroolithus. Data as of 12 October 2026.

What's changed

11 Oct 2026
Added to Omnisaura.

Every change to Omnisaura

Use this data

Download this genus as JSON With every source and licence attached. Spotted a problem? Tell us

Pictures

2 openly licensed pictures of Macroolithus on Wikimedia Commons and museum sites, each with its own author and licence.

Macroolithus sp - later cretaceous Jiangxi IMG 5164 Beijing Museum of Natural History.jpg
Bjoertvedt, CC BY-SA 4.0
TwoMacroo.jpg
Wiemann et al., CC BY-SA 4.0

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

Pictures linked from this page are credited beside each one, with their own licences; the full list is in the JSON download.