PURSUIT: SYSTEMATICS AND SPECIES DELIMITATION OF THE CLOWNFISH-HOSTING SEA ANEMONES. -TROPICAL SEA ANEMONES ARE IMPORTANT MEMBERS OF CORAL REEF COMMUNITIES AND FORM ICONIC SYMBIOTIC RELATIONSHIPS WITH CLOWNFISHES AND OTHER INVERTEBRATES. HOWEVER, NO MAJOR EFFORTS HAVE BEEN MADE TO UNDERSTAND TROPICAL SEA ANEMONE DIVERSITY SINCE THE ADVENT OF MODERN DNA SEQUENCING. COMPOUNDING A LACK OF RESEARCH, SEA ANEMONES HAVE FEW PHYSICAL CHARACTERISTICS THAT ARE USEFUL FOR DISCERNING BETWEEN SPECIES AND CLASSIC DNA SEQUENCING APPROACHES HAVE BEEN INEFFECTIVE FOR DISCOVERING NEW TAXA. THUS, IT IS LIKELY THAT TROPICAL SEA ANEMONE DIVERSITY IS VASTLY UNDERDESCRIBED, AND NEW GENOMIC APPROACHES ARE NEEDED TO SIMULTANEOUSLY DISCOVER SPECIES, PLACE THEM INTO BROADER EVOLUTIONARY CONTEXT, AND DETERMINE WHAT PHYSICAL SEA ANEMONE CHARACTERISTICS ARE INFORMATIVE AT EVERY TAXONOMIC LEVEL. THIS STUDY WILL EXPLORE THE EVOLUTIONARY PROCESSES THAT HAVE GIVEN RISE TO TROPICAL SEA ANEMONE DIVERSITY BY FOCUSING ON THE CLOWNFISH-HOSTING SEA ANEMONES. THE CLOWNFISH-SEA ANEMONE SYMBIOSIS HAS BEEN A MODEL FOR EXPLORING FUNDAMENTAL BIOLOGICAL PROCESSES, BUT PRIOR RESEARCH HAS FOCUSED ALMOST EXCLUSIVELY ON CLOWNFISH. THE PRESENCE OF UNDESCRIBED SEA ANEMONE HOSTS WILL RE-WRITE OUR UNDERSTANDING OF THE CLOWNFISH-SEA ANEMONE SYMBIOSIS, SHED LIGHT ON THE ORIGIN OF TROPICAL ANEMONE DIVERSITY, AND TRANSFORM THE INTERPRETATION OF DOZENS OF STUDIES ACROSS SCIENTIFIC DISCIPLINES. THIS RESEARCH WILL RESULT IN MODERN NATURAL HISTORY COLLECTION RESOURCES FOR TROPICAL SEA ANEMONE DIVERSITY. OUTREACH AND EDUCATIONAL OPPORTUNITIES FOR UNDERGRADUATE STUDENTS AND THE GENERAL PUBLIC WILL TAKE PLACE AT THE AMERICAN MUSEUM OF NATURAL HISTORY. CITIZEN SCIENCE INITIATIVES WILL RESULT IN THE FORMATION OF THE FIRST LONG-TERM DATA PLATFORM TO TRACK THE DISTRIBUTION AND ABUNDANCE OF THE CLOWNFISH SEA ANEMONES. UPDATED SEA ANEMONE SPECIES DESCRIPTIONS WILL BE VALUABLE FOR ESTABLISHING SCIENTIFICALLY-BASED CONSERVATION INITIATIVES IN THE ORNAMENTAL AQUARIUM TRADE. RESEARCHERS WILL CONDUCT MAJOR FIELD RESEARCH COLLECTING EXPEDITIONS TO MADAGASCAR, WESTERN AUSTRALIA, PAPUA NEW GUINEA, AND THE MARSHALL ISLANDS. ALL INDIVIDUAL SEA ANEMONES SAMPLED IN THIS STUDY WILL BE PHOTOGRAPHED UNDERWATER. RESULTING IMAGES AND ECOLOGICAL METADATA WILL BE UPLOADED TO PUBLIC DIGITAL BIODIVERSITY DATABASES. NEW SEA ANEMONE SPECIES WILL BE DISCOVERED USING RESTRICTION-SITE ASSOCIATED DNA SEQUENCING AND NEWLY DEVELOPED BAIT-CAPTURE PROBES FOR CLASS ANTHOZOA TARGETING ULTRA CONSERVED ELEMENT LOCI. RESULTING GENOMIC DATA WILL BE USED FOR TESTING THREE KEY QUESTIONS REGARDING TROPICAL SEA ANEMONE DIVERSITY AND THE CLOWNFISH-SEA ANEMONE SYMBIOSIS: 1) WHAT IS THE TRUE SPECIES-LEVEL DIVERSITY OF THE CLOWNFISH-HOSTING SEA ANEMONES? 2) DO HOST SEA ANEMONES SHARE A COMMON BIOGEOGRAPHIC ORIGIN WITH CLOWNFISHES? 3) ARE THE TROPICS A CENTER OR ORIGIN, OR ACCUMULATION, OF SEA ANEMONE BIODIVERSITY? THESE DATA, WHICH WILL BE SHARED IN PUBLIC REPOSITORIES, WILL PROVIDE THE FIRST COMPARATIVE GENOMIC SYSTEMATIC STUDY ON TROPICAL SEA ANEMONE DIVERSITY, THE CLOWNFISH-HOSTING SEA ANEMONES, AND THE ANEMONE SUPERFAMILY ACTINIOIDEA. THIS AWARD REFLECTS NSF'S STATUTORY MISSION AND HAS BEEN DEEMED WORTHY OF SUPPORT THROUGH EVALUATION USING THE FOUNDATION'S INTELLECTUAL MERIT AND BROADER IMPACTS REVIEW CRITERIA.