@article {124,
	title = {To Be or Not to Be a Flatworm: The Acoel Controversy},
	journal = {PLoS ONEPLoS ONE},
	volume = {4},
	number = {5},
	year = {2009},
	note = {Egger, Bernhard Steinke, Dirk Tarui, Hiroshi De Mulder, Katrien Arendt, Detlev Borgonie, Gaetan Funayama, Noriko Gschwentner, Robert Hartenstein, Volker Hobmayer, Bert Hooge, Matthew Hrouda, Martina Ishida, Sachiko Kobayashi, Chiyoko Kuales, Georg Nishimura, Osamu Pfister, Daniela Rieger, Reinhard Salvenmoser, Willi Smith, Julian, III Technau, Ulrich Tyler, Seth Agata, Kiyokazu Salzburger, Walter Ladurner, Peter},
	month = {May},
	abstract = {Since first described, acoels were considered members of the flatworms (Platyhelminthes). However, no clear synapomorphies among the three large flatworm taxa - the Catenulida, the Acoelomorpha and the Rhabditophora have been characterized to date. Molecular phylogenies, on the other hand, commonly positioned acoels separate from other flatworms. Accordingly, our own multi-locus phylogenetic analysis using 43 genes and 23 animal species places the acoel flatworm Isodiametra pulchra at the base of all Bilateria, distant from other flatworms. By contrast, novel data on the distribution and proliferation of stem cells and the specific mode of epidermal replacement constitute a strong synapomorphy for the Acoela plus the major group of flatworms, the Rhabditophora. The expression of a piwi-like gene not only in gonadal, but also in adult somatic stem cells is another unique feature among bilaterians. These two independent stem-cell-related characters put the Acoela into the Platyhelminthes-Lophotrochozoa clade and account for the most parsimonious evolutionary explanation of epidermal cell renewal in the Bilateria. Most available multigene analyses produce conflicting results regarding the position of the acoels in the tree of life. Given these phylogenomic conflicts and the contradiction of developmental and morphological data with phylogenomic results, the monophyly of the phylum Platyhelminthes and the position of the Acoela remain unresolved. By these data, both the inclusion of Acoela within Platyhelminthes, and their separation from flatworms as basal bilaterians are well-supported alternatives.},
	isbn = {1932-6203},
	author = {Egger, B. and Steinke, D. and Tarui, H. and De Mulder, K. and Arendt, D. and Borgonie, G. and Funayama, N. and Gschwentner, R. and Hartenstein, V. and Hobmayer, B. and Hooge, M. and Hrouda, M. and Ishida, S. and Kobayashi, C. and Kuales, G. and Nishimura, O. and Pfister, D. and Rieger, R. and Salvenmoser, W. and Smith, J. and Technau, U. and Tyler, S. and Agata, K. and Salzburger, W. and Ladurner, P.}
}
