With serpentine necks, flippers and a mouth full of needle-sharp teeth, plesiosaurs have captured imaginations since ...

One of the most distinctive features of turtles is their shell, which is actually part of their skeleton ... also an integral part of the turtle’s anatomy, including their ribcage and spine.

The way that turtles evolved into their modern form, with a shell fused to their skeleton and a beaklike face without teeth, has been described as “one of evolution’s most enduring puzzles”.