A dinosaur that died just before it was about to lay two eggs has been found by an international team of scientists.
The eggs are potato-shaped; fossilisation appears to have retained surface texture
The creature, which lived 65-98 million years ago, was discovered in China's Jiangxi Province.
The fossilised remains comprise little more than a pelvis with the shelled eggs still viewable in the body cavity.
Tamaki Sato and colleagues tell Science magazine the dinosaur's reproductive system shares similarities with both primitive reptiles and modern birds.
The animal was probably a theropod; the name describes a broad group of bipedal, largely carnivorous dinosaurs which many scientists believe gave rise to birds.
It would have been about three to four metres long.
The team says the creature's reproductive system resembled that of a crocodile in the sense that it had two ovaries and two oviducts down which eggs would be pushed, shelled and eventually laid. In contrast, modern birds have just the one ovary-oviduct combo.
However, it is clear, the team says, that this dinosaur, like birds but unlike crocodiles, could not lay all its eggs at once.
Given that nests of similar dinosaurs have been discovered with more than a dozen eggs in them, it suggests this animal would have laid two eggs and then repeated the process until her nest was full.
"It is unlikely that this specimen could have had multiple pairs of shelled eggs inside the body at one time," Tamaki Sato, from the Canadian Museum of Nature in Ottawa, and her team write in Science.
"Unless sequential egg formation and shelling was very rapid and/or there was an extremely prolonged period of egg laying, the preservation of only two tightly juxtaposed eggs in the specimen strongly indicates that each of the paired oviducts simultaneously produced a single egg."