A 161 million-year-old stegosaurus with signs of arthritis will be auctioned with an estimated price tag of between $4 million and $6 million by Sotheby’s in New York next week.

Discovered in Colorado in 2022, this nearly complete fossilized dinosaur, named “Apex,” stands 11 feet tall and measures 27 feet from nose to tail, according to Cassandra Hatton, Sotheby’s global head of science and popular culture.