In this photograph taken on March 28, 2023, in Zurich shows 'Trinity' a Tyrannosaurus Rex skeleton, which will be auctioned in Switzerland on April 18, 2023, marking the first such sale in Europe. (PHOTO / AFP)

ZURICH - Millions of years after dinosaurs ruled the Earth, the skeleton of a giant Tyrannosaurus Rex was introduced to the public in Switzerland on Wednesday ahead of its auction next month.

The giant carnivore, named TRX-293 Trinity, is expected to fetch between 5 million ($5.43 million) and 8 million Swiss francs ($8.70 million) when it goes on sale in Zurich on April 18.

Standing 3.9 meters high and measuring 11.6 meters long, Tyrannosaurus Rex is only the third T-Rex skeleton to be offered at auction, and the first in Europe

Standing 3.9 meters high and measuring 11.6 meters long, it is only the third T-Rex skeleton to be offered at auction, and the first in Europe.

"The name of this skeleton is ‘Trinity’, because it's built out of three individuals and all were found in the US," said Cyril Koller, owner of the auction house conducting the sale.

The rest of the name derives from the 293 bones in its skeleton.

Koller thought a private individual would be the likely buyer, although he was sure the public would still get to see it in future.

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In this photograph taken on March 28, 2023 in Zurich, the project manager (left) takes part in the installation of 'Trinity' a Tyrannosaurus Rex skeleton which will be auctioned in Switzerland on April 18, 2023, marking the first such sale in Europe. (PHOTO / AFP)

Discoveries of T-Rex fossils are extremely rare, said Hans Jacob-Siber, a paleontologist at the Aathal Dinosaur Museum in Switzerland.

"It’s not a cast or a copy, it’s the original. And there are very few, very few," Siber told Reuters. "In fact, until about 1970 or 1980, there used to be less than a dozen Tyrannosaurus, most of them were already in United States' museums."

Almost all of the other fossilised T-Rexes are housed in museums, meaning massive interest whenever a skeleton comes up for sale.

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Two other T-Rexes discovered in North America - called Sue and Stan - fetched $8.4 million and $31.8 million respectively when they were sold in 1997 and 2020.