Principal Investigator Abele proposes to continue his investigation of the evolutionary relationships among the suborders of decapod Crustacea. Crustacean research has recently matured greatly, owing to the adoption of cladistic techniques and high-quality ultrastructural analyses at several labs. Dr. Abele has been among the leaders, and he continues in this leadership role by being the first to learn and apply RNA sequencing techniques to the Crustacea. His work to date has concentrated on morphological, behavioral and ultrastructural data, and the proposed project would incorporate analysis of small-unit ribosomal RNA sequence data and new explorations of spermatazoan ultrastructure. Equipment will be obtained to create a molecular evolution laboratory at Florida State University dedicated to the study of crustacean evolution. The project has potential for wide impact on our understanding of crustacean systematics and evolution. It is generally accepted that molecular data will be useful in testing hypothetical relationships based on morphological and other data. This study will be among those rare projects that integrate diverse data types.