Gus, a mounted Tyrannosaurus rex skeleton is on display as part of the press previews for Geek Week Auctions at Sotheby's in New York, on July 1. Gus sold for more than $50 million. Photo by John Angelillo/UPI | License Photo

July 14 (UPI) -- A massive Tyrannosaurus rex sold for $50.1 million at Sotheby's in New York to a phone bidder making it the most expensive dinosaur fossil sold at auction.

The dinosaur was nicknamed Gus after the owner of the land in South Dakota where the bones were found.

Sotheby's did not name the buyer.

The pre-sale estimate was $20 to $30 million.