The 55ft-long specimen of the long-necked Diplodocus longus which last roamed the Earth more than 150 million years ago is believed to be the first sale of a large dinosaur skeleton at a UK auction.
Mr Albersdoerfer had been taking part in an excavation at a privately-owned quarry when he sent his sons to dig in an area nearby "to get them off his back".
To their father's astonishment, Benjamin and Jacob returned to him at the end of the day to say they had found an enormous bone.
Nine weeks later, Mr Albersdoerfer's team dug out Misty, and she was painstakingly prepared at a leading fossil laboratory in Holland before being assembled in the UK.
Errol Fuller, who has written a series of books on extinct creatures, said: "There are probably about six of these in the great museums of the world, including in Pittsburg and Washington.
"You are talking about a very rare item indeed. Even if you were lucky enough to find one in the first place, the digging out and the preparation then involved is an enormous undertaking.
"The rock that it was embedded in would have been extremely hard to break away from the bones, and you couldn't go at it with a sledge-hammer because the bones were vulnerable to breaking."
Earlier this year Leonardo DiCaprio reportedly decided not to move from his mansion in the Hollywood Hills as he didn't want to risk damaging a valuable dinosaur skeleton he had installed at the property.
Brad Pitt is also rumoured to own a dinosaur skeleton.
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70 x 57 mm complete with attractive ring