Evidence for Cnidaria-like behavior in ca. 560 Ma Ediacaran Aspidella

Research Article| August 01, 2013 Evidence for Cnidaria-like behavior in ca. 560 Ma Ediacaran Aspidella Latha R. Menon; Latha R. Menon 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK Search for other works by this author on: GSW Google Scholar Duncan McIlroy; Duncan McIlroy 2Department of Earth Sciences, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X5, Canada Search for other works by this author on: GSW Google Scholar Martin D. Brasier Martin D. Brasier 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK2Department of Earth Sciences, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X5, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Latha R. Menon 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK Duncan McIlroy 2Department of Earth Sciences, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X5, Canada Martin D. Brasier 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK2Department of Earth Sciences, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X5, Canada Publisher: Geological Society of America Received: 26 Jan 2013 Revision Received: 02 Apr 2013 Accepted: 04 Apr 2013 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (8): 895–898. https://doi.org/10.1130/G34424.1 Article history Received: 26 Jan 2013 Revision Received: 02 Apr 2013 Accepted: 04 Apr 2013 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Latha R. Menon, Duncan McIlroy, Martin D. Brasier; Evidence for Cnidaria-like behavior in ca. 560 Ma Ediacaran Aspidella. Geology 2013;; 41 (8): 895–898. doi: https://doi.org/10.1130/G34424.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The first appearance of animals in the geological record is a matter of continuing debate: how deep were the roots of the Cambrian explosion? Molecular clock estimates indicate that the deepest divergences of the Metazoa had occurred by the Ediacaran Period (635–541 Ma), yet evidence of animal activity from well below the Ediacaran-Cambrian boundary has been rare and often questionable. Meanwhile, the Ediacaran macrobiota has remained enigmatic, as emphasized by recent controversial claims that South Australia Ediacaran forms were not marine animals at all, but land-based lichens and microbial colonies. Here we report evidence for animal-like behavior in a submerged setting in a key Ediacaran form, Aspidella terranovica Billings 1872, a discoidal fossil from the ca. 560 Ma Fermeuse Formation of Newfoundland (Canada). We describe sedimentary fabrics indicating progressive vertical movement of an organism through sediment in response to an aggrading sediment-water interface. Such equilibrium traces are familiar from the Phanerozoic and are observed in partially buried marine animals such as tube anemones today. Furthermore, horizontal trails closely comparable to trails previously described from ∼565 m.y. old Mistaken Point (Newfoundland) are now linked to Aspidella. Our findings constitute evidence of both vertical and horizontal movement in a key Ediacaran taxon, consistent with an animal of cnidarian grade. Moreover, because Aspidella is also reported from the Rawnsley Quartzite of South Australia, our evidence conflicts with the proposed radical interpretation of that Ediacaran fossil assemblage. We demonstrate that at least some Ediacaran forms were probably early animals, and that they lived underwater. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.