T. rex could become most expensive fossil ever - but it's a ​problem for scientists

Here is the latest breaking news from around the world: rex could become most expensive fossil ever - but it's a ​problem for scientistsPublished30 minutes agoImage source, Matthew ShermanByEsme StallardSenior climate and science reporterIn 1997, Sotheby's hosted its first natural history auction selling fossils and other wonders of our prehistoric world. It was a niche event mostly attended by the world's museums looking for specimens to add to their collections. On the books that day was a Tyrannosaurus Rex called Sue - she was eventually sold for $8m (£6m) to the Field Museum in Chicago.

Nearly 30 years later, on Tuesday, another T. rex will make an appearance at the annual auction - one of the most complete specimens of this kind ever found. And this time it is not just scientists who are dinosaur-hunting but also the super-rich.

The Details

The new specimen, known as Gus, has already been valued at $30m but it could fetch more, possibly even becoming the most expensive dinosaur ever sold. It adds to a growing debate in the natural history world – should specimens of such scientific importance be reserved for museums and their scientists? Or - as auctioneers would argue - should fossil hunters be rewarded for their discovery of dinosaurs lost to science and saving them from a second extinction?

Cassandra Hatton, global head of natural history at Sotheby's, knows very well the lengths some fossil scientists - palaeontologists - are willing to go to in the search for these creatures. "People die on excavations," she says. And for many of these hunters, the ultimate prize is the Tyrannosaurus Rex.

This dinosaur that lived millions of years ago hardly needs describing, having been immortalised in our culture by appearances in films like King Kong and Jurassic Park, and as the namesake of an English rock band. Image source, Sotheby'sImage caption, Gus the T. rex was discovered in Badlands country in South Dakota and named after the late owner of the land"The people that look for these fossils will spend months out in the field with tents and their food in their backpacks and they're camping out in the middle of nowhere with the rattlesnakes and the bugs and the mountain lions," she explains.

What Experts Say

This is South Dakota - Badlands country - where Gus was eventually discovered 67 million years after roaming our planet. But finding it is almost the easy part, explains Dr Fiann Smithwick, an independent palaeontologist who has been collecting and preserving fossils for the past 20 years. "Suddenly when they're out of the ground, they're out of equilibrium, and that normally means they start to decay, fall apart.

"Thomas Heitkamp and the team that discovered Gus - named after the late Gary "Gus" Licking, a cattle rancher whose land it was found on - spent three years carefully excavating. "But it's not the full year," Cassandra Hatton explains. "You can only dig during the field season.

So you have to wait till the ground has thawed. And then you are furiously digging until the ground freezes again .

The development has drawn wide international attention, with diplomatic circles watching closely.