Scientists solve evolutionary puzzle on how the turtle got its shell

Scientists solve evolutionary puzzle on how the turtle got its shell: "Scientists believe they have cracked a long-standing mystery of evolution - how the turtle got its shell.

It follows the discovery in south west China last year of the oldest known turtle fossils, believed to date back 220 million years.

The three adult specimens were discovered remarkably intact and with characteristics never before seen in turtles - including teeth and an incomplete upper shell."