The fossilised remains of 'Big John', the largest triceratops dinosaur ever discovered by paleontologists, will be sold by a Paris auction house in late October, and could fetch up to 1.5 million euros ($A2.42 million).
Big John roamed the lands of modern-day South Dakota more than 66 million years ago. Paleontologists unearthed the first piece of bone in 2014 and eventually found 60 per cent of his skeleton, including a near-complete skull.
The Drouot auction house estimated Big John's skeleton would fetch between 1.2 to 1.5 million euros. Once primarily sold to museums, dinosaur remains have increasingly attracted private buyers, though their numbers remain few.
"I imagine there are about 10 buyers worldwide for this kind of piece," said Alexandre Giquello, who is leading the sale.
The skull of Big John, named after the owner of the land where more than 200 of the dinosaur's bones were found, is 2.62 metres in length - nearly a third of his overall bodylength - and two metres wide.
The name triceratops means 'three-horned face'. In the fossilised remains of his bony frill is a gaping hole, a battle scar inflicted by a smaller rival according to paleontologist Iacopo Briano.