Cryogenian evolution of stigmasteroid biosynthesis.

Sedimentary hydrocarbon remnants of eukaryotic C-C sterols can be used to reconstruct early algal evolution. Enhanced C sterol abundances provide algal cell membranes a density advantage in large temperature fluctuations. Here, we combined a literature review with new analyses to generate a comprehensive inventory of unambiguously syngenetic steranes in Neoproterozoic rocks.