A PAIR of fossilised eggs have been discovered inside the remains of a female dinosaur, shedding light on the reproductive biology of the creatures.
The uncovering in China also provides further evidence that predatory dinosaurs are the ancestors of modern birds, a once-controversial theory for which there is growing scientific acceptance.
The eggs were found in the pelvis of a female of the oviraptor family, a type of small, omnivorous dinosaur that lived during the late Cretaceous period, between 70 and 88 million years ago. The oviraptors were theropods, a group from which modern birds are widely thought to have evolved. Oviraptor means egg stealer, and the creatures were birdlike creatures that stood on two legs and grew to between six and eight feet in length, with relatively large brains, long legs, large hands, slender fingers and a powerful, toothless beak.
The name comes from a specimen found in China near a nest of eggs. Scientists initially assumed that the dinosaur was trying to snatch the eggs when it died.
More recent research, however, has suggested that it was incubating and guarding its own eggs, in similar fashion to modern birds.
Each of the eggs is about the size of a pineapple and the shape of a long potato.
They were unearthed by a team led by Tamaki Sato, of the Canadian Museum of Nature, in Ottawa, in the Nanxiong Formation, Jiangxi Province, China. The discovery, which is reported today in the journal Science, has revealed important details of dinosaur reproductive anatomy that strengthens the case that they are ancestors of birds.
The twin eggs are of a similar size, suggesting that the oviraptor has two oviducts that each produced a shelled egg at the same time.
The oviraptor's anatomy also means that the dinosaur would have laid clutches of eggs in several batches rather than all at once, in similar fashion to modern birds.
Dr Sato said: "It is unlikely that this specimen could have had multiple pairs of shelled eggs inside the body at one time."
Copyright (C) The Times, 2005
Source Citation:"Dinosaur mother bird is found with her eggs." The Times (London, England) (April 15, 2005): 25. Academic OneFile. Gale. BROWARD COUNTY LIBRARY. 11 Oct. 2009
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