Published online 10 June 2004 | Nature | doi:10.1038/news040607-6


Perfect pterosaur found in fossil egg

Find sheds light on prehistoric flying reptiles.

Unlike the hatchlings in this artist's impression, the fossil pterosaur died before it was born.Unlike the hatchlings in this artist's impression, the fossil pterosaur died before it was born.© X. Wang and Z. Zhou

The preserved bones of ancient creatures allow fossil-hunters to glimpse lives lived millions of years ago. But researchers in China have uncovered the remains of a life that was snatched away before it had even begun.

The unfortunate creature was a pterosaur, report its discoverers Xiaolin Wang and Zhonghe Zhou of the Chinese Academy of Sciences in Beijing. This group of flying reptiles were contemporaries of the dinosaurs and abounded in the Early Cretaceous period when the fossil was created, around 121 million years ago.

The embryo is very well formed, which suggests that it was probably enjoying its last few days of solitude before emerging into the prehistoric world. But it never got the chance. Wang and Zhou believe that a natural disaster such as a volcanic eruption dealt it a swift death and caused the egg to be delicately preserved.

The hapless pterosaur's misfortune is the researchers' good luck. The specimen, which includes imprints of wing and skin tissue as well as bones and shell, confirms the long-standing theory that the creatures laid eggs rather than giving birth to live young.

Laid to rest

The fossil embryo in reconstruction (top) and real life (bottom).The fossil embryo in reconstruction (top) and real life (bottom).© X. Wang and Z. Zhou

Uncovered at Jingangshan in the Liaoning province of northeastern China, the fossil is the first pterosaur embryo ever found. There is no doubt as to its identity: its well-developed shoulder and chest bones, and elongated fourth finger, mark it out as a pterosaur, the authors report in this week's Nature1.

The tiny creature also gives us new insight into pterosaur life, says Wang. At just 53 millimetres long and 41 millimetres wide, it is slightly smaller than a typical hen's egg. But the embryo boasts a 27-centimetre wingspan that would have more than quadrupled by adulthood.

What's more, says Wang, the baby beast would have been an early developer, like many modern bird chicks. "The well developed wings suggest that it would have been able to fly and feed independently of its parents soon after it hatched," he says. 

  • References

    1. Wang, X. & Zhou, Z. Nature,429, 623, doi:10.1038/429621a (2004)  | Article | ChemPort |