THE mystery of how dinosaurs laid their eggs has been solved thanks to the discovery of the first complete eggs found inside the body of the mother.
The only other eggs found in a fossilised dinosaur, in the feathered Sinosauropteryx, were too immature to have shells, so the egg-laying process was unclear. The discovery in 1993 of a brooding mother on top of her nest showed that at least some dinosaurs cared for their eggs.
The new find, in China鈥檚 Jiangxi province, shows dinosaurs laid their eggs in a series of sittings, like modern birds, rather than all at once like crocodiles and other reptiles. The fossil is a pelvis and part of a leg of a female oviraptor that lived between 100 and 65 million years ago. Oviraptors were two-legged dinosaurs, part of the theropods, a large group that includes tyrannosaurs and the ancestors of birds. Without other fossils, it is unclear whether bird-like egg laying was common to other dinosaur groups.
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Too little is preserved to identify the species, but the eggs look ready to be laid, says lead researcher Tamaki Sato of the Canadian Museum of Nature in Ottawa. The eggs are paired, showing they developed one at a time in each oviduct, and were probably laid in pairs (Science, vol 308, p 375). 鈥淚t is one of the most remarkable discoveries yet,鈥� says Ken Carpenter of the Denver Museum of Nature and Science in Colorado. 鈥淚t almost captures a female dinosaur laying her eggs.鈥�
