The status quo of higher-level metazoan phylogey based on phylogenomic analyses

Gert Wörheide
LMU München, Germany

Higher-level metazoan relationships have been controversial since the early single-ribosomal gene phylogenies have proposed the "new animal phylogeny". Nowadays, expanding molecular datasets and continuing advances in phylogenomic methods are increasingly used, aiming for a robust animal backbone phylogeny. However, while many deep intra-bilaterian relationships are largely uncontentious, several important nodes remain difficult to resolve even with large amounts of sequence data. For example, some recent large-scale metazoan phylogenomic analyses found no unequivocal support for the relationships among non-bilaterian animals, the position of acoelomorph flatworms and Xenoturbella as the sister-group to the remaining Bilateria remains debated, similar to the still unresolved position of the Chaetognatha. However, a well solved and supported backbone phylogeny of animals is needed to correctly reconstruct the evolution of the Metazoa in deep time. Some of the still open questions and remaining issues will be highlighted to open the symposium on "Molecular phylogeny: new markers and phylogenomic analyses".