Fossil steroids record the appearance of Demospongiae during the Cryogenian period

  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},
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
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.


The Ediacaran emergence of bilaterians: congruence between the genetic and the geological fossil records
The two historical records of life both suggest that although the cradle of Metazoa lies in the Cryogenian, and despite the explosion of ecology that occurs in the Cambrian, it is the emergence of bilaterian taxa in the Ediacaran that sets the tempo and mode of macroevolution for the remainder of geological time.
Oxidation of the Ediacaran Ocean
High-resolution carbon isotope and sulphur isotope records from the Huqf Supergroup, Sultanate of Oman, that cover most of the Ediacaran period indicate that the ocean became increasingly oxygenated after the end of the Marinoan glaciation and allow us to identify three distinct stages of oxidation.
Toward a Neoproterozoic composite carbon-isotope record
Glacial deposits of Sturtian and Marinoan age occur in the well-studied Neoproterozoic successions of northern Namibia, South Australia, and northwestern Canada. In all three regions, the Marinoan
Pulsed oxidation and biological evolution in the Ediacaran Doushantuo Formation
High-resolution geochemical data from the fossil-rich Doushantuo Formation in South China are reported that confirm trends from other broadly equivalent sections and highlight key features that have not been observed in most sections or have received little attention.
Two distinct glacial successions in the Neoproterozoic of Oman
Neoproterozoic glacial strata in Oman are key to the ongoing Snowball Earth discussion, providing a great opportunity to test the hypothesis. The Abu Mahara Group (Huqf Supergroup) is well exposed
Biomarker evidence for green and purple sulphur bacteria in a stratified Palaeoproterozoic sea
Hydrocarbon biomarkers from a 1.64-Gyr-old basin in northern Australia reveal a marine basin with anoxic, sulphidic, sulphate-poor and permanently stratified deep waters, hostile to eukaryotic algae, and support mounting evidence for a long-lasting Proterozoic world in which oxygen levels remained well below modern levels.
The Rise and Fall of the Ediacaran Biota
The Proterozoic and early Phanerozoic was a time punctuated by a series of significant events in Earth history. Glaciations of global scale wracked the planet, interfingered with dramatic changes in
Sterols in a unicellular relative of the metazoans
The sterol profile of the choanoflagellate Monosiga brevicollis is characterized, a representative of the unicellular sister group of animals, and genomic and biochemical information have been used together to investigate the taxonomic specificity of a fossil biomarker.
Geochronologic constraints on the chronostratigraphic framework of the Neoproterozoic Huqf Supergroup, Sultanate of Oman
The Huqf Supergroup, Sultanate of Oman, contains an important record of Neoproterozoic history, including evidence for two glaciations, a massive reorganization of the global carbon cycle, and the