The paper: http://science.sciencemag.org/content/361/6408/1246 http://science.sciencemag.org/content/361/6408/1246 Here's a bit more on what they did: >We

The paper: http://science.sciencemag.org/content/361/6408/1246 http://science.sciencemag.org/content/361/6408/1246 Here's a bit more on what they did: >We applied a new approach (17) to test the lichen, protist, and animal hypotheses by studying biomarkers extracted from organically preserved dickinsoniids. Hydrocarbon biomarkers are the molecular fossils of lipids and other biological compounds. Encased in sedimentary rock, biomarkers may retain information about their biological origins for hundreds of millions of years. For instance, hopanes are the hydrocarbon remains of bacterial hopanepolyols, whereas saturated steranes and aromatic steroids are diagenetic products of eukaryotic sterols. The most common sterols of Eukarya possess a cholesteroid, ergosteroid, or stigmasteroid skeleton with 27, 28, or 29 carbon atoms, respectively. These C27 to C29 sterols, distinguished by the alkylation pattern at position C-24 in the sterol side chain, function as membrane modifiers and are widely distributed across extant Eukarya, but their relative abundances can give clues about the source organisms (24).