Systematics and evolutionary history of Scleractinia (Cnidaria, Anthozoa)

Abstract

Corals are the subject of intense scientific, public and, therefore, media interest, particularly because of the uncertain fate of coral reefs in the face of ever increasing anthropogenic challenges. Despite their ecological importance and our economic dependence on them, we know remarkably little about the evolutionary history of this animal group known as the most important shallow and deep-water reef builders of Modern oceans. In addition to homoplasy, phenotypic plasticity, and our limited understanding of how morphological structures have evolved in each lineage, the discrepancies amongst the various evolutionary schemes are probably consequence of few morphological characters being available/used in the classification of scleractinian corals. In general, phylogenetic studies based on nucleotide sequences imply quite different evolutionary scenarios for scleractinians, particularly in terms of relationships between suborders and families. However, despite of that, to date molecular data did not contribute significantly to our understanding of the evolutionary origins of this group. Among the possible explanations for this problem, figure the fact that deep-water scleractinians have been largely neglected in molecular evolutionary studies. In the current scenario of global climate change and its impacts on the foreseeable future of this important animal group, a better understanding of their phylogenetic relationships is relevant and necessary. (AU)