Mixosaurus | 3D Dinopedia

Mixosaurus

Period of life:

250–240 mya

Period:

Triassic period

Habitat:

Coasts

Taxonomy:

Marine reptiles

Height:

0.43 m

Countries:

Triassic period Mixosaurus | 3D Dinopedia

Mixosaurus (250–240 mya)

Name Meaning

“Mixosaurus” means “mixed lizard.”

Mixosaurus is an extinct genus of ichthyosaurs that thrived during the Middle Triassic, approximately 250 to 240 million years ago. Fossils have been discovered in various parts of the world, including Italy, Switzerland, China, Timor, Canada, and the USA (Alaska and Nevada), indicating this genus was widespread in ancient seas.

In most cases, mixosaurs were relatively small ichthyosaurs, measuring between 73 and 100 cm in length and weighing between 2.2 and 5.7 kg. However, some specimens reached up to 2 meters. Their bodies were streamlined, with a long tail ending in a low tail fin—suggesting that Mixosaurus might not have been as fast a swimmer as later Jurassic ichthyosaurs. Nonetheless, the presence of a dorsal fin would have provided stability in the water.

Mixosaurus had paddle-like limbs that differed from those of later ichthyosaurs. They had five digits on each limb, whereas later ichthyosaurs often had five or more. Intriguingly, each digit contained more bones than is typical in reptiles. The front limbs were longer than the hind limbs, a trait seen in more advanced ichthyosaurs.

Its narrow jaws were armed with sharp teeth, ideal for catching fish, confirming a predatory lifestyle. The skull was relatively large in proportion to the body, distinguishing it from earlier ichthyosaurs.

Mixosaurus had about 50 vertebrae in front of the pelvic girdle—twice as many as terrestrial reptiles—indicating significant adaptations to marine life. Recent studies suggest that it likely inhabited coastal waters or shallow seas, inferred from bone structure features characteristic of creatures living in such environments.

Currently, three species of Mixosaurus are recognized: Mixosaurus cornalianus, Mixosaurus xindianensis, and Mixosaurus kuhnschnyderi, which share many traits but differ in certain features, including tooth structure.

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