A controversial tyrannosaurus bataar dinosaur skeleton sold at Heritage Auctions' Natural History Signature auction on May 20 for $1.1m, just above its $1m estimate.

The sale of the 75% complete skeleton has sparked much debate. Discovered in the past 10 years in the Gobi Desert, which spans both China and Mongolia, the sale will not be completed until a restraining order placed on the auction by the Mongolian government has been settled.

Will this dino be heading back to Mongolia?

The Mongolian president Elbegdorj Tsakhia has said that if the skeleton was discovered in Mongolia it must be returned.

Greg Rohan, president of Heritage Auctions, commented: "We have legal assurances from our reputable consignors that the specimen was obtained legally."

The 24 foot long, eight foot tall Cretaceous era specimen was a distant cousin of tyrannosaurus rex. The dinosaur was one of the main predators in modern day Central Asia around 80m years ago.

David Herskowitz, director of natural history at the auctioneer, revealed the reasons behind its strong performance. "They're incredibly rare to come across in any condition, let alone one as pristine as this," he remarked.

"Dinosaurs of this size and scarcity almost never come to market fully prepared and fully mounted like this."

An ankylosaurid skull from a saichania chulsanensis of the Cretaceous era made $62,500 at the same sale.

A 10.5 inch tyrannosaurus bataar tooth with an erupting crown sold for $37,500, while an elephant bird egg made $53,125.

Collectors have a further opportunity to own one of these rare eggs at Christie's on May 22.

The sale follows that of Samantha the triceratops, whose skull made $30,000 earlier this month.

Keep abreast of all the latest from the world of dinoasaur skeletons and other high-end collectibles by signing up for our weekly newsletter.