Palaeo-Evo-Devo of Malacostraca – quantifying crabs and their relatives

Malacostraca 的 Palaeo-Evo-Devo â 量化螃蟹及其亲属

• 批准号: 238026706
• 负责人: Professor Dr. Joachim Tobias Haug
• 金额: --
• 依托单位: Arbeitsgruppe Zoomorphologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/238026706?language=en
• 关键词: Palaeo; Evo; Devo; Malacostraca; quantifying

Crabs and their closer relatives, together representing the group Meiura, are today present in diverse ecosystems with a large number of species. Besides different marine habitats, representatives of Meiura can also be found in freshwater and terrestrial habitats. The group Meiura is of considerable economic importance, and its representatives fulfil diverse ecological roles. A large part of the ecological diversity of the group Meiura is represented by the larval stages, which comprise a significant part of the plankton. Also in the fossil record, representatives of Meiura are known in large numbers, the earliest record being from the Mesozoic. Presumably, these crustaceans have already played an important role in the ecosystems at that time. Especially in the Cretaceous representatives of the group Meiura appear to have diversified significantly, based on numerous fossils of adult crabs and close relatives. Unfortunately, almost nothing is known about the immature stages including the larvae of the fossil representatives of Meiura, even though this knowledge would be important for the understanding of fossil ecosystems. In this project, it is planned to follow a new approach to tackle the problem of the lack of fossil larvae of the group Meiura. We assume that this lack does not necessarily mean that those fossils do not exist, but instead that they are often not recognised as such. The reason for this is that especially the later larval stages, the so-called megalopa larvae, can be determined as such based on characters of the trunk and the appendages. In fossil meiurans, however, usually only the shield and/or the chelae are found. In extant meiurans, ontogenetic changes of these structures are known, yet these are rather subtle and cannot easily be detected as qualitative and discrete characters. Hence, our approach in this project is to gather quantitative data of the shape of shield and chelae and to compare these. In this way, a number of conclusions can be drawn: 1) Distinct megalopa larvae and early juvenile stages can be identified as such. 2) Ontogenetic patterns can be compared between modern and fossil representatives (palaeo-evo-devo). 3) Changes in body size of distinct stages can be detected. To quantify the shape, the outline will be investigated with Elliptic Fourier Analysis, which has already been successfully applied for similar studies. With these data, changes in different evolutionary lineages within the group Meiura should be compared. Similar changes in different lineages at the same time would imply reactions in the same direction on the same changes of the environment. In this way, such data also contribute to a general understanding of a changing climate.

螃蟹及其近亲共同代表Meiura群体，如今存在于拥有大量物种的多样化生态系统中。除了不同的海洋栖息地，Meiura的代表也可以在淡水和陆地栖息地找到。Meiura群体具有相当大的经济重要性，其代表履行各种生态角色。Meiura组的生态多样性的很大一部分是由幼虫阶段代表的，其中包括浮游生物的重要部分。此外，在化石记录中，还发现了大量Meiura的代表，最早的记录来自中生代。据推测，这些甲壳类动物已经在当时的生态系统中发挥了重要作用。特别是在白垩纪，Meiura群的代表似乎已经多样化，基于成年螃蟹和近亲的大量化石。不幸的是，几乎没有什么是已知的不成熟阶段，包括幼虫的化石代表的Meiura，即使这方面的知识将是重要的了解化石生态系统。在该项目中，计划采用新的方法来解决缺乏Meiura组化石幼虫的问题。我们认为，这种缺乏并不一定意味着这些化石不存在，而是它们通常不被承认。其原因是，特别是后期的幼虫阶段，所谓的大眼幼体，可以根据躯干和附属物的特征来确定。然而，在Meiurans化石中，通常只发现盾和/或螯。在现存的Meiurans中，这些结构的个体发育变化是已知的，但这些变化是相当微妙的，不容易被发现为定性和离散的特征。因此，我们在这个项目中的方法是收集盾形和螯形的定量数据，并进行比较。通过这种方法，可以得出一些结论：1）可以区分大眼幼体和早期幼体阶段。2)个体发育模式可以在现代和化石代表（古-演化-演化）之间进行比较。3)可以检测到不同阶段的身体大小变化。为了量化形状，将使用椭圆傅立叶分析来研究轮廓，该分析已经成功地应用于类似的研究。有了这些数据，应该比较Meiura组内不同进化谱系的变化。不同谱系在同一时间发生的类似变化意味着对环境的相同变化的相同方向的反应。这样，这些数据也有助于对气候变化的总体了解。