Porites is one of the most diverse and widely- distributed genera of living corals. It has dominated, ecologically and geologically, most tropical reefs since the Eocene (55 Mya). Porites has been the primary frame-builder of many reefs; it helps create the habitats occupied by innumerable other organisms; and its skeletons are a major constituent of some of the world's most productive Tertiary oil formations. Porites also contains preserved in its skeleton some of the most detailed paleoclimatic records available from shallow tropical seas. In this study, Porites is used as a model system for investigating the evolution of long-lived tropical marine organisms within the context of the major geophysical processes (plate tectonics and glacial sea-level fluctuations) that have shaped the world's oceans during the Cenozoic. Enzyme electrophoresis and three kinds of morphological data will be used to describe at least 80% of Indo- Pacific and Caribbean species. The data will be used to: 1. estimate ages of species and dates of divergence from common ancestors; 2. construct and compare phylogenies based on genetic and morphological similarities among the species; 3. test alternative hypotheses about the times and geological conditions favoring coral speciation; 4. examine relationships between life history characteristics, evolutionary rates and probabilities of speciation. The study is expected to resolve many chronic taxonomic problems within the genus by correlating genetic and morphological classifications, to describe previously unknown species, and to identify reliable diagnostic characters that can be used by biologists and geologists working with living and fossil material.
