Facts About Turtles:
Eunotosaurus And Turtle Evolution
More evolutionary facts about turtles are being uncovered all the time. Eunotosaurus was a small terrapin-sized creature that lived in southern Africa between 255 and 260 million years ago in a period of time called the Permian. It was during this time that all major groups of reptiles appeared.
For a long time it was thought that Eunotosaurus was the ancestor of turtles.This was based on the broad, wide ribs of the animal that gave it a shell-like back and presumably offered it some protection from predators. Not only did the ribs make it look turtle like, but the number of vertebrae and their size and structure was also the same as for turtles.
Eunotosaurus is only known from less than a dozen fossil specimens. Most of these are partial remains. Only when a specimen with a skull was found were researchers able to identify this creature as unrelated to turtles and tortoises.The skull indicated that Eunotosaurus was descended from a different branch of reptiles that was far more primitive. While details about this skull are difficult to find, it was presumably a primitive anapsid skull that did not possess any of the advanced features that define turtles as a group. There are definite similarities between Eunotosaurus and turtles, as can be seen in the partial reconstruction of the animal below. However, these features are now thought to have arisen through convergent evolution.
There is no evidence that Eunotosaurus gave rise to any other species. At the time when it lived, many groups of the most primitive reptiles were still alive. These reptiles, including Eunotosaurus, were eventually out-competed into extinction by the more anatomically advanced reptilians.
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