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Dinosaur fossil with two eggs discovered

15 April 2005

A fossil from a dinosaur about to lay two eggs has been found in China.

An international team of scientists discovered the fossil of a pelvis and hind leg, of what was probably an Oviraptor,  a two-legged dinosaur that roamed the earth between 85 and 75 million years ago. ( Oviraptor means egg thief).

The remarkable thing about the new fossil is that it has eggs, complete with shells, still inside its body. This is a rarity since most dinosaur eggs discovered have been outside an animal's body, or if found inside, have not been well-developed. Although slightly deformed, the best-preserved egg is nearly 20cm long by 6-8cm wide.

Crocodile and bird similarities

The creature's reproductive system has similarities with both crocodiles and modern birds. Crocodiles have two functional oviducts (the passage the egg takes from the ovaries to the outside of the body) and lay a clutch of eggs in one go. In contrast, birds have only one functional oviduct and lay their eggs one at a time.

The fossil discovery shows the creature had two oviducts, like a crocodile. Tamaki Sato, of the Canadian Museum of Nature in Ottawa, told the BBC that it was clear that this dinosaur, like birds and unlike crocodiles, could not lay all its eggs at once.

‘The pair of eggs show the Oviraptor developed one egg at a time in each of its two oviducts, most probably laying one pair at a time in the nest,’ Sato told the New Scientist.

Angela Milner, dinosaur expert at the Natural History Museum, says 'Nests of similar dinosaur eggs containing more than 12 eggs have been found previously in Mongolia, as has the partial skeleton of an Oviraptor brooding its nest of eggs.

The find shows that, in terms of reproductive biology, this dinosaur lies somewhere between reptiles and birds. This is consistent with the now widely accepted theory that birds evolved from dinosaurs.'

The discovery is reported in the journal Science .

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