Despite the small size of this family of fishes, the paddlefishes or Polyodontidae are of great interest to comparative anatomists and paelontologists. The two living species occur in the Yangtze river of China and in the Mississippi, and several fossil taxa are known from western North America. Drs. Bemis and Grande are studying the anatomy of the living and fossil species as well as the ontogeny of the living forms, to determine their phylogeny and historical biogeography. They are focusing on three major topics: 1. The evolutionary relationships among fossil and living paddlefishes and their significance for studies of other ray-finned fishes; 2. The origin of extreme anatomical specializations, as represented by modifications for filter feeding and elaboration of electoreceptors; and 3. The extraordinary disjunct distribution of paddlefishes in North America and China. Three practical factors make the study possible and timely: 1. Recent collecting efforts in Wyoming have produced a series of unusually well-preserved fossil paddlefishes; 2. A new fossil species from Montana has become available for analysis; and 3. Methods developed by public fish hatcheries for the culture of paddlefish allow the study of large series of developmental stages. Results from this comprehensive comparative anatomical study of living and fossil forms will improve understanding of the evolutionary history of ray-finned fishes in general and of the peculiar paddlefishes in particular.
