Fossil steroids record the appearance of Demospongiae during the Cryogenian period

  title={Fossil steroids record the appearance of Demospongiae during the Cryogenian period},
  author={G. Love and E. Grosjean and C. Stalvies and D. Fike and J. Grotzinger and A. Bradley and A. Kelly and M. Bhatia and W. Meredith and C. Snape and S. Bowring and D. Condon and R. Summons},
The Neoproterozoic era (1,000–542 Myr ago) was an era of climatic extremes and biological evolutionary developments culminating in the emergence of animals (Metazoa) and new ecosystems. Here we show that abundant sedimentary 24-isopropylcholestanes, the hydrocarbon remains of C30 sterols produced by marine demosponges, record the presence of Metazoa in the geological record before the end of the Marinoan glaciation (∼635 Myr ago). These sterane biomarkers are abundant in all formations of the… Expand
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