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domingo, 21 de outubro de 2012

Origem antiga da fauna marinha profunda moderna

quinta-feira, outubro 11, 2012

Ancient Origin of the Modern Deep-Sea Fauna


Ben Thuy1*, Andy S. Gale2, Andreas Kroh3, Michal Kucera4, Lea D. Numberger-Thuy5, Mike Reich1,5, Sabine Stöhr6

1 Geoscience Centre, University of Göttingen, Department of Geobiology, Göttingen, Germany, 2 School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom, 3 Natural History Museum Vienna, Department of Geology and Palaeontology, Vienna, Austria, 4 Marum – Centre for Marine Environmental Sciences, University of Bremen, Bremen, Germany, 5 Geoscience Centre, Museum, Collections and Geopark, University of Göttingen, Göttingen, Germany, 6 Swedish Museum of Natural History, Stockholm, Sweden



Abstract


The origin and possible antiquity of the spectacularly diverse modern deep-sea fauna has been debated since the beginning of deep-sea research in the mid-nineteenth century. Recent hypotheses, based on biogeographic patterns and molecular clock estimates, support a latest Mesozoic or early Cenozoic date for the origin of key groups of the present deep-sea fauna (echinoids, octopods). This relatively young age is consistent with hypotheses that argue for extensive extinction during Jurassic and Cretaceous Oceanic Anoxic Events (OAEs) and the mid-Cenozoic cooling of deep-water masses, implying repeated re-colonization by immigration of taxa from shallow-water habitats. Here we report on a well-preserved echinoderm assemblage from deep-sea (1000–1500 m paleodepth) sediments of the NE-Atlantic of Early Cretaceous age (114 Ma). 
 
The assemblage is strikingly similar to that of extant bathyal echinoderm communities in composition, including families and genera found exclusively in modern deep-sea habitats. A number of taxa found in the assemblage have no fossil record at shelf depths postdating the assemblage, which precludes the possibility of deep-sea recolonization from shallow habitats following episodic extinction at least for those groups. 
 
Our discovery provides the first key fossil evidence that a significant part of the modern deep-sea fauna is considerably older than previously assumed. As a consequence, most major paleoceanographic events had far less impact on the diversity of deep-sea faunas than has been implied. It also suggests that deep-sea biota are more resilient to extinction events than shallow-water forms, and that the unusual deep-sea environment, indeed, provides evolutionary stability which is very rarely punctuated on macroevolutionary time scales.

Citation: Thuy B, Gale AS, Kroh A, Kucera M, Numberger-Thuy LD, et al. (2012) Ancient Origin of the Modern Deep-Sea Fauna. PLoS ONE 7(10): e46913. doi:10.1371/journal.pone.0046913

Editor: Richard J. Butler, Ludwig-Maximilians-Universität München, Germany

Received: May 24, 2012; Accepted: September 6, 2012; Published: October 10, 2012

Copyright: © 2012 Thuy et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: The study was funded by the German Research Foundation (http://www.dfg.de/index.jsp), grant RE2599/6-1, and by the European Union funded Synthesys program (http://www.synthesys.info/), grants SE-TAF-2674 and SE-TAF-2969. Deposition of the described material in the collections of the Natural History Museum in London (UK), the micropaleontological collection at the University of Tübingen (D) and the Geoscientific Museum at the University of Göttingen (D) was done with the permission of the respective institutes. 
 
We acknowledge support by the German Research Foundation and the Open Access Publication Funds of the Göttingen University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

* E-mail: nebyuht@yahoo.com

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