Mesosaur

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Mesosaurs Fossil range: Early Permian
Skeleton of Mesosaurus.
Conservation status
-pre
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Subclass: Anapsida Order: Mesosauria Family: Mesosauridae Baur, 1889
Genera
Brasileosaurus Stereosternum Mesosaurus

Mesosaur ("middle lizards") were an order of small marine reptiles that lived during the early Permian period, roughly 320 to 280 million years ago. Mesosaurs were the first aquatic reptiles, having returned to a watery way of life after evolving on land.

[edit] Mesosaurus

The most well-known mesosaur is Mesosaurus itself. Fossils of the animal were found in Namibia, Africa [1] and parts of South America, such as Brazil, Uruguay, and Paraguay. [2] The widespread distribution of the fossil - particularly in those areas of Africa and South America which, when viewed on a map of the Earth, appear to 'interlock' - helped to reinforce the idea of continental drift. [3] [4]

Mesosaurus resembled a small alligator, although the most common specimens are only 40 centimeters in length. Nonetheless, the largest specimen is almost 2 meters in length, and Mesosaurus was probably the largest land animal of its time. It is believed to have fed on fish, or possibly crustaceans, by using its teeth as a sieve, rather like modern-day whales.