A spirited 15-minute bidding war between online and phone participants ultimately landed the ultra-rare specimen with an anonymous buyer, far surpassing its initial estimate of $2-4 million.

The dinosaur skeleton is one of only four known Ceratosaurus nasicornis skeletons and the only juvenile skeleton of the species, which resembles the Tyrannosaurus rex but is smaller.

The “Largest Piece of Mars on Earth” just sold at auction for about $5.3 million— $5,296,000, to be exact. Popular Science has reached out to Sotheby’s for confirmation of the sale price.