Possible evidence of cell division, differentiation found in oldest known embryo fossils

A group of 15 scientists from five countries has discovered evidence of cell differentiation in fossil embryos that are more than 550 million years old. They also report what appear to be cells about to divide. They used x-ray imaging technologies that produce higher resolutions than hospital-CT scans and digitally extracted cells from the embryos of ancient animals that have been preserved in the Doushantuo Formation, a fossil site in South China.