‘Virtually complete’ Stegosaurus fossil to be auctioned at Sotheby’s geek week

<span>The Stegosaurus ‘Apex’ fossil is valued at between $4m-$6m.</span><span>Photograph: Matthew Sherman/Sotheby’s</span>
The Stegosaurus ‘Apex’ fossil is valued at between $4m-$6m.Photograph: Matthew Sherman/Sotheby’s

The largest and most complete Stegosaurus fossil ever found is expected to fetch up to $6m (£4.7m) when it is sold as the star lot in Sotheby’s “geek week” auction this summer.

At 11ft (3.4 metres) tall and more than 20ft long the “virtually complete” fossil, which has been nicknamed “Apex”, is more than 30% larger than “Sophie”, the previously most intact stegosaurus specimen which was on display in London’s Natural History Museum.

Cassandra Hatton, the qglobal head of science at Sotheby’s, said: “Apex marks an incredibly important milestone, as simply one of the best fossils of its kind ever unearthed.

“Stegosaurus is one of the most universally recognisable dinosaur species, whose unmistakable silhouette has been a source of fascination and wonder for generations. Through the careful process of excavation, preparation, and installation, Apex sets a new standard for all future discoveries of this magnitude, and further reinforces the enduring appeal of stegosaurus and its vaunted status in popular culture.”

With an auction estimate of $4m-$6m it may become one of the most valuable dinosaur fossils ever sold at auction. The record is held by Stan, a T rex skeleton auctioned off by Christie’s for $31.8m in 2020.

However, the dinosaur auction market was plunged into crisis in 2022 when Christie’s was forced to call off the £20m auction of another Tyrannosaurus rex skeleton, called Shen, just days before it was due to go under the hammer after a well-known palaeontologist raised concerns that parts of the specimen looked too similar to Stan.

Apex was discovered by the commercial palaeontologist Jason Cooper in the Morrison Formation, in Moffat County, Colorado, near the town of Dinosaur, in May 2022.

Sotheby’s said it had “collaborated closely” with Cooper to “document the entire process, from discovery and excavation to restoration, preparation, and mounting”, ensuring that the documentation and salewas “handled with the highest standards and transparency”. Apex will be on exhibition at Sotheby’s galleries in New York before the sale in July.

The Stegosaurus is the best-known member of the armoured dinosaurs (Thyreophorans), characterised by the distinctive shape and arrangement of dermal armour on its back, extending from the neck to the tail.

The Apex fossil shows “no signs of combat or predation-related injuries; however, evidence of arthritis indicates that it lived to an advanced age”. It also has “an impressive femur length of 45 inches”.

Sotheby’s said Cooper, the founder of Trilobites of America and the co-owner of Dinosaur Corporation, had “unearthed numerous dinosaur specimens” within the US, many of which were now “housed in institutions around the globe, with a significant number having been donated by him”.