By Daniel Schweimler
BBC News, Buenos Aires
The international black market in fossil remains is a lucrative one
Four tonnes of dinosaur bones and other fossils stolen from Argentina are back home after they were seized while being sold on the US black market.
They were welcomed in Buenos Aires at a formal ceremony attended by senior Argentine military officers, diplomats and the US ambassador to Argentina.
US police recovered the relics after Interpol received a tip-off.
The haul is thought to be the largest ever quantity of fossil material to come onto the black market.
An Argentine air force band played by the airport runway as a Hercules military transport plane landed and unloaded several well-wrapped crates containing the fossils, which included tree trunks, prehistoric crab claws and much more.
All had been stolen from Argentina - probably mixed with rocks and minerals exported to the United States.
They were discovered - some wrapped in Argentine newspapers - two years ago being sold at a mineral fair in Tucson, Arizona, after an anonymous tip-off to Interpol.
But it is not easy to move such a vast quantity of dinosaur bones and it has taken until now to bring them home.
The US ambassador in Buenos Aires, Earl Anthony Wayne, who has a keen personal interest in rocks and bones, was one of those responsible for bringing the prehistoric cargo back to Argentina.
He was at the airport to see it arrive.
"There probably are more out there and we'll keep looking for it," he said as the bones arrived.
He said the international community should keep working to improve information-sharing about the black market for palaeontological relics.
"This was clearly a good tip that came in in this case that led people to be able to follow that path and discover this."
The cargo has been taken to the Bernardino Rivadavia natural history museum in Buenos Aires where the material will be sorted and returned to the provinces in which they were found.
Southern Argentina is rich in dinosaur remains with new ones, sometimes previously unknown species, being discovered on a regular basis.
However, the black market trade in prehistoric remains is a lucrative one and Argentina is delighted to get this particular cargo back.