Old Turtle vs. New Turtle (IMAGE) University of the Witwatersrand Caption A recent study on the oldest proto turtle, <i>Eunotosaurus</i> (left), suggests the broadening of the ribs in turtles was initially an adaptation for burrowing to escape the extremely arid environment of South Africa 260 million years ago. Later the ribs were incorporated into the modern protective turtle shell as found in <i>Pelusios</i> (right). Credit Luke Norton Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.