The Stylet

Diversity and Systematics of Acoela and Nemertodermatida

Mitochondrial genome data support the basal position of Acoelomorpha and the polyphyly of the Platyhelminthes

Publication Type:Journal Article
Year of Publication:2004
Authors:I. Ruiz-Trillo, Riutort, M., Fourcade, H. M., Baguna, J., Boore, J. L.
Journal:Molecular Phylogenetics and Evolution

We determined 9.7. 5.2. and 6.8kb, respectively, of the mitochondrial genomes of the acoel Paratomella rubra, the nemertodermatid Nemertoderma westbladi, and the free-living rhabditophoran platyhelminth Microstomum lineare. The identified gene arrangements are unique among metazoans, including each other, sharing no more than one or two single gene boundaries with a few distantly related taxa. Phylogenetic analysis of the amino acid sequences inferred from the sequenced genes confirms that the acoelomorph flatworms (acoels + nemertodermatids) do not belong to the Platyhelminthes, but are, instead, the most basal extant bilaterian group. Therefore, the Platyhelminthes, as traditionally constituted, is a polyphyletic phylum. (C) 2004 Elsevier Inc. All rights reserved.

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