An exceptionally well-preserved 65- million-year-old fossilised dinosaur nest with some broken eggs exposing tiny skeletons is up for auction in Los Angeles.
The nest of raptors, fierce predatory dinosaurs, is expected to fetch around US$200,000 ($295,000).
"It is probably one of the finest dinosaur egg nests in the world.
"For the tiny skeletons still to be inside the eggs, folded up beautifully like this, means that they had to be almost ready to hatch," said Thomas Lindgren, consulting director of Natural History for auctioneers Bonhams and Butterfields.
Mr Lindgren said the 22-egg nest, encased in sandstone and containing 10 complete embryos, originated in China.
It had been in the hands of private collectors in Asia for the past 20 years before being sold to an American.
Tens of thousands of dollars have been spent on scientific preparation and studies to determine exactly to which of the six to eight known species of small raptor the nest belonged.
That will be revealed in an academic paper being prepared.
The auction, which also includes several prehistoric skeletons and dinosaur bones, teeth and partial nests, comes at a time of renewed international interest in dinosaurs, particularly in Asia where several nations are building museums.
"Dinosaurs are hotter than ever. It is a very collectible market especially for higher-quality specimens," Mr Lindgren said.
He said the nest might remain in private hands rather than going to a museum, at least initially.
"Unfortunately, most museums are slow at being able to put together funding at short notice.
"But that doesn't mean it won't end up going to an institution."