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

鲟鱼类是分布于北方的一个鱼类类群，据信大约在1.5亿年前从其他鳍状鱼类（辐鳍鱼）中分离出来。活鲟鱼（25种）的形态基本上保持不变，因为他们第一次进化。尽管有许多关于鲟鱼形态学的研究，但从来没有一项研究足够详细或全面，以允许现代研究它们的进化。希尔顿、格兰德和比米斯对化石和活鲟鱼骨骼的最新研究有两个主要目标。第一个目标是详细描述短吻鲟鱼（Acipenser brevirostrum）的骨骼，短吻鲟鱼是一种小型鲟鱼，发现于北美东部沿海河流。这项研究将基于几种类型的标本，包括干燥的骨骼，手工清洁的储存在酒精中的骨，以及清洁和染色的骨骼（其中软组织是透明的，软骨是蓝色的，骨骼是红色的）。代表所有生命史阶段的标本将被研究，从最早的胚胎到最古老的标本。这种方法允许观察由于骨骼的生长和发育而引起的形态学变化。本研究的结果将以大幅面专著的形式发表，并附有照片作为文件，线条作为解释，同时附有明确的文字说明。其目的是，这本专着将作为一个持久的贡献，以了解解剖的鲟鱼和标准参考解剖研究的原始射线鳍鱼。本研究的第二部分涉及追踪生活和化石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，只有在对一个群体的活成员进行详细研究之后，这些标本才能得到正确的解释。此外，在研究的第一部分中产生的新的比较数据将用于制定新的关系假设。由于种种原因，以往对鲟鱼亲缘关系的形态学研究都是不够的。例如，许多研究只关注来自特定地理区域或国家的鲟鱼的关系。进化并没有发生在政治边界内，希尔顿、格兰德和比米斯的研究将是第一个在世界范围内收集所有鲟鱼形态学数据的研究。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。许多鲟鱼不稳定的保护状态使得研究它们的进化史变得更加重要。

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.