Hoshino, Y.Poshibaeva, A.Meredith, W.Snape, C.Poshibaev, V.Versteegh, G. J. M.Kuznetsov, N.Leider, A.van Maldegem, L.Neumann, M.Naeher, S.Moczydlowska, M.Brocks, J. J.Jarrett, A. J. M.Tang, Q.Xiao, S.McKirdy, D.Das, S. K.Alvaro, J. J.Sansjofre, P.Hallmann, C.2018-01-282018-01-282017-09-012375-2548http://hdl.handle.net/10919/81945Sedimentary hydrocarbon remnants of eukaryotic C₂₆–C</sub>30</sub> sterols can be used to reconstruct early algal evolution. Enhanced C₂₉ 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. Our results show that the capacity for C₂₉ 24-ethyl-sterol biosynthesis emerged in the Cryogenian, that is, between 720 and 635 million years ago during the Neoproterozoic Snowball Earth glaciations, which were an evolutionary stimulant, not a bottleneck. This biochemical innovation heralded the rise of green algae to global dominance of marine ecosystems and highlights the environmental drivers for the evolution of sterol biosynthesis. The Cryogenian emergence of C₂₉ sterol biosynthesis places a benchmark for verifying older sterane signatures and sets a new framework for our understanding of early algal evolution.7 pagesenCreative Commons Attribution-NonCommercial 4.0 Internationalmarinoan snowball-earthneoproterozoic glaciationshydrocarbon biomarkerssouth-australiataoudeni basinnorth chinabiostratigraphic significanceisotope stratigraphymolecular fossilssiberian-cratonArticle - Refereedhttps://doi.org/10.1126/sciadv.170088739Xiao, S [0000-0003-4655-2663]