Systematics, Ontogeny, Osteology and Historical Biogeography of Paddlefishes (Chondrostei: Polyodontidae)

尽管这种鱼的体型很小，但比较解剖学家和海洋动物学家对白鳍鱼或多齿鱼科非常感兴趣。这两个物种生活在中国的长江和密西西比河中，北美西部发现了几个化石类群。Bemis博士和Grande博士正在研究活物种和化石物种的解剖学以及生命形式的个体发育，以确定它们的系统发育和历史生物地理。他们主要关注三个主题：1.化石和活的白鳍鱼之间的进化关系及其对其他鳍鱼研究的意义；2.极端解剖特化的起源，以滤食和电感受器的改良为代表；3.北美和中国白鳍鱼的异常分离分布。三个实际因素使这项研究成为可能和及时：1.怀俄明州最近的采集工作产生了一系列保存异常完好的白鳍鱼化石；2.蒙大拿州的一种新化石物种已可用于分析；3.公共鱼类孵化场开发的养殖白鳍鱼的方法允许研究大系列的发育阶段。这种对生物和化石形态的全面比较解剖学研究的结果将有助于加深对鳍鱼一般的进化史的理解，特别是对特殊的白鳍鱼的了解。

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.