NEW YORK — A Virginia fossils dealer was sentenced Tuesday to three months in prison even after a prosecutor described his cooperation with law enforcement in heroic terms, saying he enabled more than 18 largely complete dinosaur fossils to be located, enough for Mongolia to open its first dinosaur museum.

Eric Prokopi, 39, was sentenced by U.S. District Judge Alvin Hellerstein for smuggling a 70-million-year-old Tyrannosaurus skeleton from Mongolia into the United States by making false statements to U.S. officials, including that the then-unassembled bones were merely reptile fossils from Great Britain.

Once assembled, the skeleton was sold by Dallas-based Heritage Auctions for more than $1 million before it was seized by the U.S. government and returned to Mongolia.