We found a matchYour institution may have access to this item. Find your institution then sign in to continue.TitleFossil steroids record the appearance of Demospongiae during the Cryogenian period.AuthorsLove GD; Grosjean E; Stalvies C; Fike DA; Grotzinger JP; Bradley AS; Kelly AE; Bhatia M; Meredith W; Snape CE; Bowring SA; Condon DJ; Summons REPublicationNature, 2009, Vol 457, Issue 7230, p718ISSN1476-4687Publication typearticleDOI10.1038/nature07673