The Anisian (Middle Triassic) ammonoids of Nevada - An integrated approach to understand morphological change

中三叠世早期Anisian期，Panthalassa西海岸氨类变异性高，分类和形态多样性显著。在美国内华达西北部，华丽的露头为我们提供了了解世界这一地区开放水域动物群的最佳视角。因此，我们的方法的特点是将整体设计作为主要的高质量方法。大部分材料可以从内华达州沙漠中广阔的露头中收集，但数据集计划由我们在加利福尼亚的一个合作伙伴的收藏品和华盛顿国家博物馆收藏的适合我们方法的部分来完成。本研究旨在阐明菊石的形态差异、环境变化、咬痕表达的捕食压力以及适应导致的间接形态变化之间的复杂相互作用。我们计划使用多元统计（PAST， R）来区分外壳形态，以获得变异性的全面视图。在此基础上，我们希望通过对各剖面的分类和形态多样性变化的分析，揭示其随时间变化的形态变化，并阐明其进化途径。后者也将在我们的一个美国合作伙伴的支持下成为可能，他在检验进化论假说方面非常有资格。我们的整体研究主题与二叠纪/三叠纪界线之后开始的生态系统全面重组的中生代海洋革命（MMR）密切相关。三叠纪菊石的强烈辐射，构成了宏观生物量的主要组成部分，并伴随着它们潜在捕食者的新发展。在海洋爬行动物中，根据这种特殊的颌和牙齿组织，脐龙可能专门从事粉碎贝壳，并且在波恩和柏林工作组同时申请的建议中重点关注。通过波动不对称分析对形态变化的发展背景进行评估，增加了我们建议的复合观点。这将基于几何形态测量方法（包括地标），由三维模型实现。后者我们打算从菊石的摄影测量中产生。

In the Anisian stage of the early Middle Triassic ammonoid variability is high off the western coast of Panthalassa and the taxonomic and morphological diversity is remarkable. Superb outcrops in NWNevada in the United States provide the best insight into open water faunas of this part of the world. Thus our approach is characterized by an overall design as a primarily high quantity approach. The largest part of the material can be collected from the spacious outcrops in the desert of Nevada, but the data set is planned be completed by collections of one of our co-operation partner in California and by those parts of the National Museum collection in Washington that are suitable for our approach. Our proposal aims to elucidate the complex interplay between morphological disparity in ammonoids, environmental change, predation stress expressed by bite marks as well as indirect morphological change by adaption. We plan to use multivariate statistics (PAST, R) to discriminate between shell morphologies to obtain a comprehensive view of variability. Based on the taxonomic and morphologic diversity change in the sections we expect to unravel the expected morphological change through time and to elucidate evolutionary pathways. The later will be possible also by support of one of our American co-operation partners who is highly qualified in testing evolutionary hypotheses. Our overall research topic is strongly connected to the Mesozoic Marine Revolution (MMR) that started after the Permian/Triassic boundary with a full reorganisation of ecosystems. The intense radiation of ammonoids in the Triassic, constituting a main portion of macroscopic biomass and falls together with a new development of their potential predators. Among marine reptiles Omphalosaurus was possibly specialised in shell crushing according to this peculiar jaw and teeth organization, and are focussed on in the proposals applied for simultaneously by the Bonn and Berlin working-groups. The compound view of our proposal is added by an assessment of the developmental background of morphological change by a fluctuating asymmetry analysis. This is projected to be based on geometric morphometric methods (including landmarks), enabled by three-dimensional models. The latter we intend to generate from the photogrammetry of ammonites.