A Tyrannosaurus rex fossil billed as one of the world’s largest and most complete specimens has sold for a record $50.1 million at an auction. Sotheby’s said the 67-million-year-old fossil, nicknamed “Gus,” is now the most expensive set of dinosaur bones ever auctioned off, besting the almost $45 million price tag for a nearly complete stegosaurus sold by the same New York auction house in 2024. Before that, another T. rex sold for nearly $32 million in 2020. The fossil is about 63% complete. It was discovered in 2021 in South Dakota. The auction house said Tuesday’s mystery buyer outbid six others.