The purpose of this collaborative research by Prof. Ann Budd at University of Iowa and Prof. Nancy Knowlton at University of California, San Diego, is to clarify evolutionary relationships among reef-building corals. The plan for research includes a detailed re-analysis of four related families, which together comprise about one half of the major groups (genera) of reef-building corals. Preliminary research suggests that current assumptions about relationships and corresponding definitions of families and genera are seriously flawed. In particular, one third of all Atlantic corals belong to a previously unrecognized family that is distinct from many other conventionally recognized families in the Pacific. In a particularly extreme example, Atlantic corals currently assigned to different families are in fact more closely related to each other than they are to their supposed close relatives in the Pacific. The investigators will use modern molecular and morphological methods to study taxonomic and phylogenetic relationships of these corals. Mitochondrial and nuclear genes will be sequenced, and coral skeletons will be sectioned in order to observe fine details (microstructure). Molecular and morphological characters will then be analyzed using computer-based methods to derive a family tree. The results will be made available on web sites as well as in the scientific literature (including an illustrated taxonomic monograph), and the investigators will also host a workshop at the International Coral Reef Symposium that is held once every four years. Coral reefs are the most diverse of all marine habitats, and among the most threatened. As such, there have been numerous suggestions for how to prioritize conservation efforts. Most of these are based on species numbers, and for that reason Atlantic corals have been considered relatively trivial from a biodiversity perspective. In a recent high-profile paper, for example, only 4 of 18 identified biodiversity hotspots were in the Atlantic. However, scientists and the public have long recognized that evolutionary distinctiveness is also an important criterion for making conservation decisions; hence, for example, the interest of the public in coelacanths and other living fossils. This research will for the first time provide a modern evolutionary framework for these reef-building corals, so that evolutionary distinctiveness as well as species numbers can be considered when evaluating conservation options. This is particularly important in light of the discovery of a major radiation of corals limited to the Atlantic, since Atlantic corals have declined by 80% across much of their range over the last three decades.