Fossil Bird Embryo Found in China

Chinese scientists have discovered a 121 million-year-old baby bird that was fossilized while still curled in its egg, the journal Science reported Thursday.

The fossil is thought to be the most ancient unborn bird ever discovered. It is distinctive because of its feathers, which do not appear in many modern flying birds when they first hatch. The scientists said the discovery supports the view that birds developed the strategy of hatching featherless only later in their evolution.

This fossil is interesting because its preservation is so exceptionally fine, that even the soft tissues like feathers have been preserved, Angela Milner of London’s Natural History Museum told BBC News Online. For an embryo that is still inside the egg, it is surprising how advanced the feathers were.

The scientists know the bird was an embryo because the fossil is tucked up in a characteristic way for an unhatched chick.

The tucked posture of the fossil is consistent with a late-stage embryo rather than with a hatchling, in which case the head would have raised beyond the vicinity of the feet, Zhonghe Zhou and Fucheng Zhang from the Chinese Academy of Sciences, wrote in the Science paper.