Fossil steroids record the appearance of Demospongiae during the Cryogenian period

@article{Love2009FossilSR,
  title={Fossil steroids record the appearance of Demospongiae during the Cryogenian period},
  author={Gordon D. Love and Emmanuelle Grosjean and Charlotte Stalvies and David A. Fike and John P. Grotzinger and Alexander S. Bradley and Amy E. Kelly and Maya P. Bhatia and Will Meredith and Colin E. Snape and Samuel A. Bowring and Daniel J. Condon and Roger Everett Summons},
  journal={Nature},
  year={2009},
  volume={457},
  pages={718-721}
}
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… 
Evolution of Precambrian life in the Brazilian geological record
Abstract Precambrian rocks comprise nearly one-quarter of the surface of Brazil and range from Paleoarchean (ca. 3.6 Ga) to the latest Ediacaran (0.542 Ga) in age. Except for controversial
Possible animal-body fossils in pre-Marinoan limestones from South Australia
The Neoproterozoic era was punctuated by the Sturtian (about 710 million years ago) and Marinoan (about 635 million years ago) intervals of glaciation. In South Australia, the rocks left behind by
The earliest Cambrian record of animals and ocean geochemical change
The Cambrian diversification of animals was long thought to have begun with an explosive phase at the start of the Tommotian Age. Recent stratigraphic discoveries, however, suggest that many taxa
The molecular record of Cryogenian sponges – a response to Antcliffe (2013)
MOLECULAR fossils or lipid biomarkers, which are preserved in ancient sedimentary rocks and petroleum that have undergone a mild thermal history, have been studied for over five decades (e.g.
Possible poriferan body fossils in early Neoproterozoic microbial reefs
TLDR
Petrographically identical vermiform microstructure from approximately 890-million-year-old reefs is presented, which would provide the first physical evidence that animals emerged before the Neoproterozoic oxygenation event and survived through the glacial episodes of the Cryogenian period.
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