http://www.livescience.com/animalwor...il_embryo.htmlThe discovery of spherical fossils that resemble tiny baseballs could reveal how the earliest known egg-laying organism developed from embryo to adulthood.[font=arial] In 1998, researchers discovered thousands of 600-million-year-old fossilized embryos in the Doushantuo Formation, a fossil deposit in South China. Two years later, the same team unearthed fossils of a tubular coral-like animal, called Megasphaera ornata, which appeared to be grown-up versions of the embryos discovered earlier.
The case for a relationship between the two fossil types now has been strengthened by the recent discovery of about 80 intermediate-stage fossils that have traits in common with both groups.
The finding, to be detailed in the February issue of the journal Geology, could provide the missing link between egg and adult versions of one of Earth’s earliest animals.