Contact: Susan Trulove
Caption: A more-than 551 million year old four-cell embryo magnified using a scanning electronic microscope. The specimen is about 0.65 millimeter in diameter.
Credit: Shuhai Xiao
Usage Restrictions: May be used to illustrate reports about Shuhai Xiao's research.
Related news release: Possible evidence of cell division, differentiation found in oldest known embryo fossils