Dino card No. 1798 of 2,027

Tiamat

Say it: tee-AH-mat

Name means: “named after Tiamat, the serpentine goddess of Sumerian and Babylonian mythology”1

Ate: PlantsLong-necksEarly Cretaceous to Late Cretaceous

Tiamat was a long-necked, plant-eating dinosaur that lived in what is now Brazil. It had a small head, a very long tail, and walked on four sturdy legs. Scientists think it was one of the earliest titanosaurs, the group that includes some of the biggest dinosaurs ever.1 3

Lived

113 to 94 million years ago3

Early Cretaceous to Late Cretaceous

Fossils found in

Açu Formation, Potiguar Basin, Ceará state, Brazil1 3

Food

Plants3

Length

10 to 100 m2

estimate from PBDB adult length range

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 22 cars parked in a rowas long as 560 bananas end to end

How big was Tiamat compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

cool stuff

Fun facts

Tiamat is the first dinosaur ever named from the Potiguar Basin in Brazil, though other dinosaur remains have been found there.1

The only known fossils of Tiamat are nine tail vertebrae from the beginning and middle of the tail.1

Tiamat lived during the middle Cretaceous period, about 113 to 94 million years ago.2

Scientists think Tiamat was a basal titanosaur, meaning it was an early relative of the giant titanosaurs like Argentinosaurus.1

An isolated titanosaur osteoderm (a bony plate in the skin) found in 2018 might also belong to Tiamat.1

The species name valdecii honors Dr. Valdeci dos Santos Júnior, who discovered the fossil site.1

AI-made picture of Tiamat — An AI-made picture of how Tiamat might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

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For dino experts

Scientific name: Tiamat
Named by: Pereira et al. 20243
Group: Long-necks
Family / clade: Titanosauria3
Classification: Sauropodomorpha > Sauropoda > Titanosauria > Macronaria3
Age of the rocks: 113 to 94 million years (Albian / Cenomanian)3
Rock formations: Açu3
Countries: Brazil3
Fossil records: 1 in the Paleobiology Database3
Discovery: Tiamat was named in 2024 by Pereira and colleagues based on nine tail vertebrae found in the Açu Formation of Brazil. The fossils were discovered by Dr. Valdeci dos Santos Júnior.1
Still debated: Scientists are not sure exactly how big Tiamat was, because only tail bones have been found. They also debate whether an isolated osteoderm belongs to this dinosaur.1 2

Where the facts come from

Tiamat valdecii (en.wikipedia.org)
PBDB Taxon (paleobiodb.org)
Tiamat in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.

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