Supported by

The 150-million-year-old specimen is valued at up to $6 million by Sotheby’s. Some paleontologists worry this auction and earlier ones are driving fossil market speculators.

By Asher Elbein

In 1999, Brock Sisson was 16 years old and working at the Museum of Ancient Life in Utah. He was handed a box and warned not to drop it. Inside sat the upper jaw and nose horn of a young Ceratosaurus, a 150-million-year-old predatory dinosaur.

In July, Sotheby’s will auction off that specimen, estimating its value at $4 million to $6 million. The sale arrives about a year after the Sotheby’s auction of “Apex” the stegosaurus, which sold to the hedge fund billionaire Kenneth Griffin for $45 million.