A Tyrannosaurus rex fossil named “Gus” became the most expensive dinosaur ever to sell at auction on Tuesday.
Gus sold for $50,130,000—far above the estimated $20-million to $30-million price tag that had been set earlier by the auction house Sotheby’s.
The skeleton stands about 12.5 feet (3.8 meters) tall and is approximately 38 feet long—the dinosaur’s skull alone is some 4.5 feet long, according to Sotheby’s, and weighs so much that it must be handled separately. (The skull mounted on the fossil skeleton that is currently displayed at the auction house is a replica.) The skeleton is estimated to be about 61 percent complete, and Sotheby’s said this makes it among the most complete T. rex fossils ever found.
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Gus is unusual, according to the auction house, because the fossil retains some bones called gastralia. Also known as “belly ribs,” gastralia are free-floating bones located in the abdominal wall. Today they are still found in certain reptiles, such as crocodiles and tuatara.
The 67-million-year-old skeleton of “Gus” the T. rex, which was found during an excavation on private land in South Dakota and comprises 183 fossil bones, representing up to 80 percent of the animal’s total bone mass.
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The fossil was discovered in 2021 on a South Dakota ranch. It is believed to be roughly 67 million years old. The bones bear evidence of bite marks from other tyrannosaurs, and Sotheby’s said these may have been “sustained by either combat or post-mortem scavenging.” Gus also shows signs of “injuries which occurred during the life of the individual, with fractured and healed bones discernable in several ribs and gastralia,” according to the auction house.
The value of Gus eclipses that of “Stan,” another T. rex fossil found in South Dakota, which was sold for $31.8 million in October 2020 and is now in a history museum in Abu Dhabi, and the Stegosaurus “Apex,” which was bought for $44.6 million by billionaire Ken Griffin in 2024. Gus went to an unknown phone bidder.
Scientists have long criticized the practice of auctioning off dinosaur fossils like these. Researchers have argued that allowing private buyers to own such specimens deprives paleontologists the opportunity to study them. And the extreme prices the fossils command mean most museums or academic institutions can’t compete in a bidding war.