Molecular phylogenetic analyses of crustaceans

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This project will contribute sequence data of crustacean taxa that are required for the metazoan phylogeny that is being inferred in the Priority Programme 1174. After four years of data acquisition the main goal is to understand alignment patterns and assumptions implied in data analyses methods that produce errors in phylogenetic trees. We want to evaluate available evidence to support clades in the Curstacea part of the arthropod tree. The current reconstructions of phylogenetic relationships of and within the Crustacea are still very competing and diverging. Within the project we want to test the monophyly of Entomostraca, the Maxillopoda concept, the monophyly of Thecostraca, the position of Mystacocarida, Remipedia, Cephalocarida and Malacostraca, the Thoracopoda concept, the Palliata hypothesis. In cooperation with other groups we want to infer the exact position of the Insecta or Tracheata considering data from insects, myriapods, crustaceans and chelicerate taxa. We are responsible for the crustacean data. Therefore there are two levels of analyses: Within the single project (phylogeny within Crustacea) and within the Priority Programme (arthropod phylogeny). In the last funding period we want especially add data for the still missing Remipedia, Mystacocarida, Cephalocarida, and Pentastomida, using the 454 sequence technology. Applications of complex substitution models (especially allowing for time-heterogeneity) improved our analyses, but nevertheless artefacts still appear. The most difficult task is to discover false clade support and effects of hidden long branches. In close cooperation with the coordination project we will use new tools for analyses of alignment patterns to contribute to a better understanding of animal phylogeny.