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

内华达州的阿尼西期（中三叠世）菊石 - 了解形态变化的综合方法

基本信息

批准号：
321792813
负责人：
Professor Dr. Jens Lehmann
金额：
--
依托单位：
Keck Graduate Institute of Applied Life Sciences
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/321792813?language=en
关键词：
Anisian Middle Triassic ammonoids Nevada

项目摘要

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.

在中期三叠纪早期的氨基变异性的Anisian阶段，Panthalassa的西部海岸很高，分类学和形态学多样性非常出色。美国NWNEVADA的出色露头为世界上这一地区的开放水域动物群提供了最好的见解。因此，我们的方法的特征是总体设计主要是高量方法。可以从内华达州沙漠的宽敞露头收集最大的材料，但计划通过我们在加利福尼亚州的合作伙伴之一以及华盛顿国家博物馆收藏的那些部分适合我们方法来完成数据集。我们的建议旨在阐明氨基型中形态差异，环境变化，捕食应力与咬合标记表达的捕食应力以及通过适应性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数据（过去，R）来区分壳形态，以获取可变性的全面视图。根据分类学和形态学多样性的变化，我们期望通过时间来揭示预期的形态变化并阐明进化途径。也将通过我们的一位美国合作伙伴的支持，他们在测试进化假设方面具有支持。我们的整体研究主题与中生代海洋革命（MMR）密切相关，该革命（MMR）始于二叠纪/三叠纪边界，并完全重组生态系统。三叠纪在三叠纪中的强烈辐射，构成了宏观生物量的主要部分，并掉落了其潜在捕食者的新发展。在海洋爬行动物中，Omphalosaurus可能会根据这个奇特的下巴和牙齿组织而专门从事壳粉碎，并专注于由波恩和柏林工作组同时应用的建议。通过评估形态变化的发育背景通过波动的不对称分析来添加我们建议的复合观点。预计这是基于几何形态学方法（包括地标），由三维模型启用。我们打算从氨矿的摄影测量法生成后者。