In 2024, Apex, a stegosaurus skeleton, set a new benchmark for the fossil market when it sold for US$44.6 million with fees at Sotheby’s New York to Ken Griffin, founder of hedge fund Citadel.
Two years later, the auction house is bringing Gus to market – one of the largest and most complete Tyrannosaurus rex skeletons ever discovered. Unearthed in the American Midwest and measuring nearly 11.6 metres long, the fossil carries an estimate of US$20 million and will be offered in New York on 14 July.
With Sotheby’s recent increases to its buyer’s premium, a hammer price of US$38.2 million or more would see Gus overtake Apex as the most expensive fossil in auction history.
Lot 20 | Gus | A mounted Tyrannosaurus rex skeleton
Late Cretaceous, Maastrichtian Stage (approx. 67 million years ago)
Hell Creek Formation, Harding County, South Dakota, USA
Length: approximately 11.6 m; height: approximately 3.8 m
Provenance:
- Excavated on private land in Harding County, South Dakota, over field seasons in 2021, 2022 & 2023
Estimate: US$20,000,000 - 30,000,000
Auction House: Sotheby's New York
Sale: Natural History including Gus Rex
Date and Time: 14 July 2026 | 10:00 pm (New York local time)
Due to scavengers, natural decay and the movement of rock over millions of years, it is virtually impossible for a dinosaur skeleton to be excavated completely intact. Even museum specimens are often supplemented with casts to fill in missing bones for display and academic research.
Since the first Tyrannosaurus rex was identified in 1902, only about 32 relatively complete adult T. rex skeletons have been found worldwide. Of these, just three preserve more than 60% of their original bone count.
One is Sue, which consists of 250 real bones – nearly 73% of a full skeleton – and sold for US$8.36 million at Sotheby’s New York in 1997. Another is Stan, with around 188 original bones, or roughly 63% of the skeleton, which realised US$31.84 million at Christie’s New York in 2020. The third is Gus, the star of Sotheby’s upcoming sale, which comprises 183 original bones, amounting to about 61% of a complete T. rex.
Sue and Stan each set new auction records for a fossil when they came to market. Today, Sue is on view at the Field Museum in Chicago, while Stan is housed at the newly opened Natural History Museum Abu Dhabi.
Gus is approximately 61% complete by bone count
Gus’ left third metatarsal bone in the field
The value of a dinosaur fossil depends not only on how many bones survive, but also on how much of the original bone mass they represent. Sue’s bone material is thought to be around 90% original, Stan’s about 70%, and Gus comes in at roughly 75-80%. In other words, most of the missing elements in these three T. rex specimens are relatively small, less critical bones.
In Gus’ case, the skull – often the most valuable part of a T. rex skeleton – is especially well preserved, with approximately 82% of the bones represented, including all six dentitions.
An adult T. rex could grow to more than 12 metres in length and weigh over 5,000 kilograms. Armed with an enormous bite force and around 60 razor‑sharp teeth that were replaced throughout its life, it could tear through prey with formidable efficiency, bones and all. Some scientists have even suggested that, if a T. rex were somehow transported into the present day, its jaws would be powerful enough to crush a car in a single bite.
Research also points to a highly developed diencephalon – a key part of the forebrain that serves as the body’s central control and relay hub – giving T. rex vision comparable to that of an eagle. Combined with an acute sense of smell, this would have made tracking and locating prey remarkably effective.
Gus has an exceptionally preserved skull, with approximately 82% of the bones represented
Another factor that affects the value of a dinosaur skeleton is the bundle of rights that comes with it.
As with any branded object, owning the physical piece does not automatically confer control of the intellectual property. When Stan the T. rex sold, for instance, the rights to produce 3D replicas or sell related merchandise online were not included, which limited its commercial potential.
By contrast, the record‑breaking stegosaurus Apex, the third‑most‑expensive fossil – a juvenile Ceratosaurus – and now Gus all come to market with full associated rights. Their buyers are able to license the image, create toys, sell replicas or even issue NFTs based on the specimens.
Detail of Gus’ complete right foot, and near-complete left foot
Gus’ caudal vertebrae and associated chevrons
Gus was excavated between 2021 and 2023 in the Hell Creek Formation in the American Midwest, and takes its name from the landowner on whose property it was found, Gary “Gus” Licking.
Stretching across Montana, North and South Dakota, and Wyoming, Hell Creek is one of the richest sources of dinosaur fossils in North America. The first relatively complete T. rex skeleton, as well as Sue and Stan, all came from this formation.
The site has also yielded many of the Cretaceous period’s best‑known dinosaurs, including Triceratops, Pachycephalosaurus, Ankylosaurus and Edmontosaurus.
Gus carries an estimate of US$20 million, some distance below the current auction record for a fossil. But rare, relatively complete dinosaur skeletons have a history of blowing past their estimates. The three highest prices for fossils at auction to date are:
- Apex the Stegosaurus | Sold: US$44.6 million (est. US$4 million), Sotheby's New York, 2024
- Stan the Tyrannosaurus rex | Sold: US$31.84 million (est. US$6 million), Christie's New York, 2020
- A juvenile Ceratosaurus skeleton | Sold: US$30.51 million (est. US$4 million), Sotheby's New York, 2025
Apex, largest and most complete known Stegosaurus fossil | Sold: US$44.6 million, Sotheby's New York, 2024
Stan, Tyrannosaurus rex skeleton | Sold: US$31.84 million, Christie’s New York, 2020
The only known juvenile Ceratosaurus fossil | Sold: US$30.51 million, Sotheby's New York, 2025