The evolutionary timeline is constantly evolving -- being tweaked to adopt and adapt to new discoveries, new facts, new understandings. Thanks to a geologist at Virginia Tech and a team of researchers from Chinese Academy of Sciences, the storyline of multicellular organisms is likely to be shifted back 60 million years to account for new evidence of complex organisms.

The researchers say their analysis of fossils trapped in the rocks of the Doushantuo Formation in central Guizhou Province of South China -- dating back some 600 million years -- show evidence of cooperation among multiple cells. The phosphorite rocks encase complex multicellular fossils which exhibit qualities of early plants and animals like cell-to-cell adhesion, differentiation, and programmed cell death.

In the new study, scientists argue the fossils, many of which look oddly like pepperoni pizzas, are evidence that the transition from single- to multi-cell organisms was solidified some 60 million years earlier than previously thought -- 60 million years before most complex organisms began showing up in the geological timeline as part of the Cambrian Explosion.

"This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way," study author Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science, said in a press release.

"Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals," Xiao added. "This paper lets us put aside some of those interpretations."

The study was published this week in the journal Nature.