Earlier this year, dinosaur fossils had been a boon to the auction houses: Christie’s sold a Deinonychus skeleton for $12.4 million, and a Gorgosaurus skeleton went for $6.1 million at Sotheby’s.

Look for the sagittal suture – the squiggly line that runs the length of the skull – and note whether is it's completely fused. If it is, the remains are likely to be of someone older than 35.

An almost complete dinosaur skeleton found connected from its hind skull to its tail has been discovered in Montouliers, France. Damien Boschetto Sign up for CNN’s Wonder Theory science newsletter .