The skeleton of a 40-foot (12-meter) dinosaur nicknamed “Stan”, one of the most complete Tyrannosaurus rex specimens ever found, will be auctioned in New York next month and could set a record for a sale of its kind.

Discovered in 1987 near Buffalo, South Dakota, the 188-bone skeleton took more than three years to excavate and reconstruct by paleontologists from the state’s Black Hills Geological Research Institute, where it has been exhibited since.