(photo in article) How the turtle shell evolved has puzzled scientists for years, but new research sheds light on how their hard shells were formed. Scientists say the ancient fossil skeleton of an extinct South African reptile has helped bridge a 30 to 55-million-year gap. This ancestor of the modern turtle, Eunotosaurus, is thought to be around 260 million years old. It had significant differences to a recently found fossil relative. Eunotosaurus was discovered over a century ago but new research in the journal Current Biology has only now analysed its differences to other turtle fossils. Eunotosaurus africanus Skeleton...