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Fossil steroids record the appearance of Demospongiae during the Cryogenian period

Fossil steroids record the appearance of Demospongiae during the Cryogenian period Chemical fossils discovered in sedimentary rocks in Oman provide the earliest evidence for animal life so far discovered. The fossil steroids — 24-isopropylcholestanes characteristic of sponges of the Demospongiae class — date back 635 million years or more to around the time of the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. This suggests that the shallow waters in some late Cryogenian ocean basins contained dissolved oxygen in concentrations sufficient to support simple multicellular organisms at least 100 million years before the rapid diversification of bilaterians during the Cambrian explosion. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Nature Springer Journals

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References (88)

Publisher
Springer Journals
Copyright
Copyright © 2009 by Macmillan Publishers Limited. All rights reserved
Subject
Science, Humanities and Social Sciences, multidisciplinary; Science, Humanities and Social Sciences, multidisciplinary; Science, multidisciplinary
ISSN
0028-0836
eISSN
1476-4687
DOI
10.1038/nature07673
Publisher site
See Article on Publisher Site

Abstract

Chemical fossils discovered in sedimentary rocks in Oman provide the earliest evidence for animal life so far discovered. The fossil steroids — 24-isopropylcholestanes characteristic of sponges of the Demospongiae class — date back 635 million years or more to around the time of the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. This suggests that the shallow waters in some late Cryogenian ocean basins contained dissolved oxygen in concentrations sufficient to support simple multicellular organisms at least 100 million years before the rapid diversification of bilaterians during the Cambrian explosion.

Journal

NatureSpringer Journals

Published: Feb 5, 2009

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