Phylogenetic studies in the brown algae with emphasis on the genus Cystoseira (Fucales)

Phylogenetic hypotheses about the brown algae have long been dominated by the concept that life history pattern and thallus construction are of fundamental importance for the inference of evolutionary history and that annual filamentous forms are ancestral. DNA sequence studies over the last few years have challenged this view. Recent comprehensive studies employing an increased taxon set and extensive DNA sequence data have turned the classical brown algal phylogenetic tree upside down. An update will be presented on the most recent insights. Subsequently an introduction will be given about a study that has recently been initiated and is intended to unravel relationships between species of the fucalean genus Cystoseira, which has its centre of diversity in the Mediterranean Sea. At least 44 species are thought to exist of which 33 occur in the Mediterranean of which 19 are Mediterranean endemes, while the rest extends its distribution into the Atlantic Ocean. Preliminary results indicate that the genus may not be monophyletic, that there is great variation between clades and minimal variation within clades.