Prehistoric Animal Museum

Meet today’s friendEarly mosasaur reptile

Dallasaurus

Four small legs with toes, a slender body and a long tail.

Dallasaurus was a small early mosasaur, about one metre from head to tail. Look for its four little legs and toes, then follow the long tail behind.

Still model of Dallasaurus on a transparent background

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Dallasaurus

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Preparing the Dallasaurus exhibit.

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Guide for grown-ups

When it lived: Late Cretaceous
Where fossils were found: Texas, USA, North America
Body length: 1 m (about 3 ft)
Diet: Meat-eater
What kind of animal?: Early mosasaur reptile. Dallasaurus was an early mosasaur that lived near the coast during the Late Cretaceous. Its limbs retained toes, and their bones support the interpretation that it could still move on land.

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Narration transcript

Dallasaurus was a small early mosasaur, about one metre from head to tail. Look for its four little legs and toes, then follow the long tail behind.

Research notes about Dallasaurus

Research summary

Fossils of Dallasaurus date to the Late Cretaceous and have been found in Texas, USA, North America.

Learning from fossils

About one metre is an estimate of its body length, rather than its standing height.
Its fossils show limbs that could still be used on land. Its exact swimming style, skin colour and display movements are reconstructed.

Scientific sources

Dallasaurus turneri, a new primitive mosasauroid from the Middle Turonian of TexasAccessed 2026-10-28
The evolution of mosasaurid foraging behavior through the lens of stable carbon isotopesAccessed 2026-10-28
Mosasaurine limb-bone anatomy and aquatic adaptationAccessed 2026-10-28

Leon Made This compiled these research notes from public museum resources and scientific papers while preserving uncertainty in the reconstruction. Last reviewed 2026-10-28.

3D model and asset credits

Dallasaurus: Model by Julian Johnson-Mortimer (FreddyFoxFreddy); museum preparation by Leon Made This. Creative Commons Attribution 4.0 International

Open source and licensing

The code is licensed under AGPL-3.0. Original science writing and project artwork use CC BY-NC-SA 4.0 for non-commercial sharing. The brand policy prevents impersonation, and third-party assets keep their original licences.

View the GitHub project Read the full licensing notes

Official source

Made by Leon Made This

Prehistoric Animal Museum is made and maintained by Leon Made This. Use these addresses to verify the official project and its creator.

Official Prehistoric Animal Museumhttps://leon-made-this.work/museum/en/Leon's personal websitehttps://leon-made-this.work/

More information is available below.

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Leon Made This

About this museum

A little museum made by a developer dad for his daughter

I’m Leon, a developer and a dad. When my daughter was three, dinosaur chases on television frightened her, so I made a 3D prehistoric animal museum where she could look quietly and listen only when she wanted to.

The museum is free, with no sign-up, adverts or visitor tracking. Finding one interesting detail at a time is plenty.

Official source

Made by Leon Made This

Prehistoric Animal Museum is made and maintained by Leon Made This. Use these addresses to verify the official project and its creator.

Official Prehistoric Animal Museumhttps://leon-made-this.work/museum/en/Leon's personal websitehttps://leon-made-this.work/

View the source on GitHub Read the licence and asset notes