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

在1995- 1996年的南极夏季野外季节，在南极洲的沙克尔顿冰川地区发现了已知最古老的小龙虾化石和已知最古老的小龙虾化石洞穴之一。该奖项支持一项合作的跨学科研究，以扩大这些发现。小龙虾爪发现于2.8 ~ 3亿年前冰川环境下的上石炭统—下二叠统宝塔组；这一发现将小龙虾首次出现的时间推迟了6500万到7500万年。这些小龙虾的洞穴是在大约2.4亿年前沉积的下三叠统弗雷莫组中发现的。它们的丰富和复杂性表明，小龙虾在其漫长的历史中很早就发展出了穴居行为。本研究的目的是在南极洲收集更多的小龙虾身体和痕迹化石，利用这些化石进一步了解晚石炭世-早二叠纪和早三叠纪期间该大陆部分地区的沉积条件，并研究淡水类十足类（小龙虾）的早期进化和穴居历史。具体来说，工作计划是：1)在宝塔组寻找更多的小龙虾化石和小龙虾洞穴；2)解释了宝塔组小龙虾的生活方式，并将其与小龙虾的形态联系起来；3)重建含螯虾岩所记录的沉积环境和古气候；4)在Fremouw组的洞穴中寻找小龙虾；5)定量描述Fremouw组的洞穴；6)比较晚石炭世至早二叠世的小龙虾和洞穴的形态和行为与早三叠世及以后的小龙虾和洞穴的形态和行为。本研究将阐明小龙虾的进化史和行为史。在许多不同的水生生态系统中，现代小龙虾对能量流、生物种类组成和生物丰度等参数具有重要的控制作用。本研究将提供有关这种环境和行为多样化发生的方式和时间的信息，并增加对晚古生代和早中生代古气候的了解。

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.