Comparative Osteology and Phylogenetic Relationships of Fossil and Living Sturgeons (Actinopterygii, Acipenseriformes)

摘要鲟鱼、白鳍鱼和它们的化石近亲形成了一小群来自北半球的鱼类，称为鲟形鱼类，据信是在大约1.5亿年前从其他射线鳍鱼(放线蕨类)中分离出来的。生活鲟鱼(25种)的形态自首次进化以来基本保持不变。尽管有许多关于鲟鱼形态的研究，但从来没有一项足够详细或全面的研究来进行现代研究它们的进化。希尔顿、格兰德和贝米斯对鲟鱼和生活鲟鱼骨架的最新研究有两个主要目标。第一个目标是详细描述短鼻鲟鱼(Acipenser Brevirostrum)的骨架，这是一种发现于北美东部沿海河流的小型鲟鱼物种。这项研究将基于几种类型的标本，包括干燥的骨骼，保存在酒精中的手工清洗的骨骼，以及清除和染色的骨骼(其中软组织清晰，软骨被染成蓝色，骨骼被染色成红色)。将研究代表所有生命历史阶段的标本，从最早的胚胎到可用的最古老的标本。这种方法可以观察骨骼生长和发育过程中的形态变化。这项研究的结果将以大型专著的形式出版，配有图片以供记录，线条用于解释，并附有清晰的文字说明。其目的是，这本专著将作为对鲟鱼解剖学知识的持久贡献，并为原始鳍鱼的解剖学研究提供标准参考。这项研究的第二部分涉及追踪活的和化石的鲟鱼之间的进化关系。大多数被鉴定为鲟鱼的化石都是非常零碎的，只有在对一个群体中的活着成员进行详细研究后，才能对这些标本进行适当的解释。此外，在研究的第一部分产生的新的比较数据将被用来形成新的关系假设。由于种种原因，以往所有关于鲟鱼关系的形态研究都不够充分。例如，许多研究只研究了来自特定地理区域或国家的鲟鱼之间的关系。进化不是在政治范围内发生的，希尔顿、格兰德和贝米斯的研究将第一次纳入全球范围内所有鲟鱼的形态数据。所有种类的鲟鱼都受到某种形式的保护，其中许多被列为濒危物种。许多鲟鱼处于不稳定的保护状态，这使得研究它们的进化史变得更加关键。

ABSTRACT Sturgeons, paddlefishes and their fossil relatives form a smallgroup of fishes from the Northern hemisphere called Acipenseriformes thatis believed to have split off from other ray-finned fishes (theactinopterygians) some 150 million years ago. The morphology of livingsturgeons (25 species) has remained largely unchanged since they firstevolved. Although there have been many studies of sturgeon morphology,there never has been a study that is detailed or comprehensive enough toallow modern studies of their evolution. The new study of the skeleton offossil and living sturgeons by Hilton, Grande and Bemis has two main goals.The first objective is to describe in detail the skeleton of the shortnosesturgeon (Acipenser brevirostrum), a small species of sturgeon found incoastal rivers of eastern North America. This study will be based onseveral types of specimens, including dry skeletons, hand cleaned skeletonsthat are stored in alcohol, and cleared and stained skeletons (in which thesoft tissue is made clear, cartilage is stained blue and bone is stainedred). Specimens representing all life history stages will be studied, fromthe earliest embryos to the oldest specimens available. Such an approachallows observations of changes of morphology due to growth and developmentof the skeleton. The results of this study will be published in a largeformat monograph, illustrated with photographs for documentation and linedrawings for interpretation, accompanied by clear text descriptions. Theintention is that this monograph will serve as a lasting contribution tothe knowledge of the anatomy of sturgeons and a standard reference foranatomical studies of primitive ray-finned fishes. The second part of this study concerns tracing evolutionaryrelationships among living and fossil sturgeons. Most fossils that areidentified as sturgeons are very fragmentary, and only after a detailedstudy of the living members of a group can such specimens be properlyinterpreted. Additionally, new comparative data generated during the firstpart of the study will be used to formulate new hypotheses ofrelationships. All previous morphological studies of the relationships ofsturgeons are inadequate for various reasons. For instance, many studieshave looked only at relationships of sturgeons from a particular geographicregion or country. Evolution has not occurred within political boundaries,and Hilton, Grande and Bemis' study will be the first to incorporatemorphological data for all sturgeons on a worldwide scale. All species ofsturgeons are afforded some form of protection, with many listed asendangered. The precarious conservation status of many sturgeons makestudies of their evolutionary history even more critical.