Collaborative Investigation of Earliest Crayfish: Paleobiologic, Paleoecologic, and Paleoclimatic Implications

米勒：吉9614709伊斯贝尔：吉9615045巴布科克：吉9614989 摘要 在1995年至1996年的南极夏季，在南极洲的沙克尔顿冰川地区发现了最古老的小龙虾化石和最古老的小龙虾洞穴化石。 该奖项支持合作，跨学科的研究，以扩大这些发现。 小龙虾的爪子是在2.8亿至3亿年前的冰川环境中沉积的上石炭纪至下二叠世宝塔组中发现的;这一发现将小龙虾的首次出现推迟了6500万至7500万年。 这些小龙虾洞穴是在大约2.4亿年前沉积的下三叠统Fremouw地层中发现的。 它们的丰富性和复杂性表明，小龙虾在其漫长的历史中很早就发展了穴居行为。 这项研究的目的是从南极洲收集更多的小龙虾尸体和遗迹化石，利用这些化石进一步了解该大陆部分地区晚石炭世-早二叠世和早三叠世的沉积条件，并研究淡水虾类十足类（小龙虾）的早期进化和穴居历史。 具体的工作计划是：1）在宝塔组中寻找更多的螯虾化石和螯虾洞穴; 2）解释宝塔组中螯虾的生活方式并将其与螯虾形态联系起来; 3）重建含螯虾岩石记录的沉积环境和古气候; 4）在Fremouw组中寻找洞穴中的螯虾;（5）定量描述Fremouw组洞穴，（6）将晚石炭世至早二叠世的螯虾和洞穴与早三叠世及以后的螯虾和洞穴的形态和行为进行比较。 这项研究将阐明小龙虾的进化和行为历史。 现代淡水螯虾在许多不同的水生生态系统中对能量流动、生物种类组成和生物丰度等参数发挥着重要的控制作用。 这项拟议的研究将提供有关这种环境和行为多样化如何以及何时发生的信息，并增加对晚古生代和中生代早期古气候的了解。

Miller: OPP 9614709 Isbell: OPP 9615045 Babcock: OPP 9614989 Abstract During the 1995-96 Austral summer field season the oldest known fossil crayfish and one of the oldest known occurrences of fossil crayfish burrows were found in the Shackleton Glacier area of Antarctica. This award supports a collaborative, interdisciplinary study to expand on these discoveries. The crayfish claw was found in the Upper Carboniferous to Lower Permian Pagoda Formation deposited in glacial environments 280 to 300 million years ago; the discovery pushes back the first occurrence of crayfish 65 to 75 million years. The crayfish burrows were found in the Lower Triassic Fremouw Formation deposited approximately 240 million years ago. Their abundance and complexity indicate that crayfish developed burrowing behavior early in their long history. The objectives of the study are to collect additional crayfish body and trace fossils from Antarctica, to use these fossils to develop further insight into the depositional conditions in parts of that continent during intervals of the Late Carboniferous- Early Permian and the Early Triassic, and to study the early evolutionary and burrowing history of freshwater astacoid decapods (crayfish). Specifically, the work plan is: 1) to search for more fossil crayfish and crayfish burrows in the Pagoda Formation; 2) to interpret the way of life of the crayfish in the Pagoda Formation and relate it to the crayfish morphology; 3) to reconstruct the depositional environment and paleoclimate recorded by the crayfish-bearing rocks; 4) to search for crayfish within burrows in the Fremouw Formation; 5) to quantitatively describe the burrows in the Fremouw Formation; and 6) to compare the morphology and behavior of Late Carboniferous to Early Permian crayfish and burrows to those of the Early Triassic and later. This study will elucidate the evolutionary and behavioral history of crayfish. Modern crayfish exert an important control on paramet ers such as energy flow, biotic species composition, and biotic abundance in many different aquatic ecosystems. This proposed study will yield information about how and when this environmental and behavioral diversification took place, as well as increase understanding of the late Paleozoic and early Mesozoic paleoclimates.