A dinosaur that looks like a miniature T. rex is now one of the world's most expensive fossils.

The rare skeleton of a Nanotyrannus — recently confirmed to be a distant cousin of Tyrannosaurus rex, not just a young specimen — sold for $47.3 million to a mystery buyer at auction in New York City on Tuesday, according to Sotheby’s. The auction house had expected it to fetch anywhere from $6 to $9 million.

The blockbuster price tag for “Jodi,” as the skeleton is nicknamed, makes it the second-priciest set of dinosaur bones ever sold. This summer, a T. rex fossil known as “Gus” sold for a record $50.1 million at Sotheby's .

The winning bidder for “Jodi” has, for now, chosen to remain anonymous after outbidding five other prospective buyers online and by phone during the roughly 12-minute live auction, Sotheby’s said.

A Nanotyrannus was about half the length of an adult T. rex, and the two creatures coexisted during the Cretaceous period some 67 million years ago.…