How Turtles make shells?

Turtles are one of the only animals on Earth to form shells outside their bodies through the fusion of modified ribs, vertebrae and shoulder bones. This week, scientists have announced the discovery of a fossilised, 260-million-year-old turtle ancestor that pushes the origins of the turtle shell back 40 million years further than we thought.

Find out more: http://bbc.in/15mOsc2

Photo credit: Luke Norton