Big John, 66 million years old and the largest triceratops skeleton ever unearthed at eight metres long, goes up for auction in Paris on Thursday. 

He is expected to fetch up to €1.5 million at the Drouot auction house. 

Big John's skeleton is 60 per cent complete, and was unearthed in South Dakota, United States in 2014 and put together by specialists in Italy. 

He lived during the Upper Cretaceous period, the final era of the dinosaurs, and died in a floodplain, buried in mud that kept him very well preserved. 

A horn injury near his cranium suggests he got into at least one nasty fight. 

It is the latest dinosaur to be sold by the Drouot auction house which, according to its website, handled an allosaurus and a diplodocus each worth 1.4 million euros in 2018.

The price tag means that museums are largely excluded from the purchase. 

"We can't compete," said Francis Duranthon, director of the Toulouse Museum of Natural History. 

He said €1.5 million represented 20 to 25 years of his acquisitions budget.

But auctioneer Alexandre Giquello said there was a good chance it would still be seen by the public. 

He told AFP that half of those expressing an interest in Big John had stated their desire to show it in a museum, and it was not clear how the others felt. 

Scientists had also been able to analyse the bones before the auction.

The triceratops is among the most distinctive of dinosaurs due to the three horns on its head – one at the nose and two on the forehead – that give the dinosaur its Latin name. 

Dinosaur sales can be unpredictable, however: in 2020, several specimens offered in Paris did not find takers after minimum prices were not reached.