Echinoderms are a phylum of invertebrates that include starfish, sea urchins and cucumbers, crinoids ("sea lilies"), sand dollars, and several extinct groups, known only from the fossil record. One theory regards the echinoderms as the ancestral group from which vertebrates arose. The evolutionary relationships and history of diversification within the echinoderms has been the subject of research for many decades, and data from fossils, skeletal morphology, and most recently, DNA sequences have been amassed for this purpose. These studies have also attempted to place the echinoderms in the evolutionary framework of other major animal groups. Dr. Edward Ruppert is a leading specialist in invertebrate developmental and comparative biology, and he proposes research on the internal anatomy of echinoderms, with particular attention to the axial complex, which controls the water vascular system. The proposed research will have wide-ranging impact. The new anatomical data will help to interpret the functional anatomy of a diverse and worldwide group, and these data may help resolve many remaining questions surrounding the group's evolution. An independent data set such as this will be compared with existing data, such as the DNA sequences, opening opportunities for future research on the mosaic nature of evolution among different character systems. The results of this study will have a wide audience beyond echinoderm specialists.
