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Article Addendum

The Diploblast-Bilateria sister hypothesis: parallel evolution of a nervous systems in animals

Bernd Schierwater, Sergios-Orestis Kolokotronis, Michael Eitel and Rob DeSalle

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For many familiar with metazoan relationships and body plans, the hypothesis of a sister group relationship between Diploblasta and Bilateria1 comes as a surprise. One of the consequences of this hypothesis - the independent evolution of a nervous system in Coelenterata and Bilateria - seems highly unlikely to many. However, to a small number of scientists working on Metazoa, the parallel evolution of the nervous system is not surprising at all and rather a confirmation of old morphological and new genetic knowledge.^2-4 The controversial hypothesis that the Diploblasta and Bilateria are sister taxa is, therefore, tantamount to reconciling the parallel evolution of the nervous system in Coelenterata and Bilateria. In this addendum to Schierwater et al.,¹ we discuss two aspects critical to the controversy. First we discuss the strength of the inference of the proposed sister relationship of Diploblasta and Bilateria and second we discuss the implications for the evolution of nerve cells and nervous systems.

Schierwater B, Eitel M, Jakob W, Osigus HJ, Hadrys H, Dellaporta SL, Kolokotronis SO, DeSalle R. Concatenated analysis sheds light on early metazoan evolution and fuels a modern "urmetazoon" hypothesis. PLoS Biol 2009; 7:e1000020

Authors

Bernd Schierwater Corresponding author: bernd.schierwater@ecolevol.de

ITZ, Ecology and Evolution, Tierärztliche Hochschule Hannover, Germany; and American Museum of Natural History, New York

Sergios-Orestis Kolokotronis

American Museum of Natural History

Michael Eitel

ITZ, Ecology and Evolution, Tierärztliche Hochschule Hannover, Germany

Rob DeSalle Corresponding author: desalle@amnh.org

American Museum of Natural History

This is an open-access article

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