"Brazen! It is brazen!" Prof Paul Sereno says down the phone line from Chicago.
He makes no effort to disguise his anger that a rare meteorite from Mars discovered two years ago in the West African nation of Niger ended up being auctioned off in New York last month to an unnamed buyer.
The palaeontologist, who has close connections with the country, believes it should be back in Niger.
This millions-of-years-old piece of the Red Planet, the largest ever found on Earth, fetched $4.3m (£3.2m) at Sotheby's. Like the buyer, the seller was kept anonymous.
But it is unclear if any of this money went to Niger.
