Evolutionary and developmental patterns of Cretaceous uncoiled ammonites

白垩纪展开菊石的演化和发育模式

• 批准号: 268237660
• 负责人: Dr. René Hoffmann
• 金额: --
• 依托单位: Institut für Geologie, Mineralogie und Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/268237660?language=en
• 关键词: Evolutionary; developmental; patterns; Cretaceous; uncoiled

The heteromorph ammonoids (i.e., ammonoids that deviate in their coiling from the planispiral, regular coiling) belong to the most enigmatic fossil groups, but their origin, palaeobiology, and functional morphology is still a matter of debate. Little is known about possible reasons why ammonoid iteratively deviated from normal coiling and instead realise a putatively disadvantageous conch construction with respect to buoyancy control and locomotion. Furthermore little is known why they became successful clades in terms of taxonomic diversity and morphological disparity especially during the Cretaceous. Within the proposed project, these uncoiled ammonoids will be analysed with respect to their morphospace occupation by the use of relevant characters such as conch geometry, shell ornamentation, and suture line. Selected taxa (depending on availability of material) from the Cretaceous will be studied including possible sexual dimorphism, intraspecific variability, and variation in ontogenetic traits. Their wide geographical distribution and high abundances, fast evolutionary rates, and the preservation of the entire ontogeny due to accretionary shell growth made especially Mesozoic ammonoids a perfect fossil group to study evolutionary scenarios with respect to palaeoecological perturbations. The main goal of this project is (1) to test various hypotheses of the origin of Cretaceous heteromorph ammonites, (2) to evaluate the species and genus concepts as well as validity of higher taxonomic entities and their phylogenetic relationships, (3) to investigate palaeoecological parameters and their possible influence on the conch geometry, and (4) to compare diversity and disparity patterns with respect to ontogenetic traits. Here we make a first attempt to analyse the intraspecific variability of Cretaceous heteromorph ammonites and discuss them with respect to their deviation in coiling and conch form from monomorph ammonoids. With this study we will improve the understanding of the phylogenetic relationships, palaeobiology, palaeoecology, and stratigraphic range of the Cretaceous uncoiled ammonites. The Cretaceous period is characterised by transgressions/regressions, warming/cooling events and oceanic anoxic events which made it ideal to study the appearance and distribution of specific heteromorph shell morphologies and hopefully detected characteristic patterns. In comparison with normally coiled ammonites from contemporaneous deposits the influence of distinct palaeoenvironmental changes (water depth, temperature, oxygen) and their effect on the heteromorph shell geometry can be tested.

异形菊石（即，菊石的卷曲与平面螺旋的规则卷曲不同，属于最神秘的化石群，但它们的起源、古生物学和功能形态学仍然是一个有争议的问题。关于菊石为什么反复偏离正常卷曲，而是实现相对于浮力控制和运动的puperous不利的海螺构造的可能原因知之甚少。此外，很少有人知道为什么他们成为成功的分支在分类多样性和形态差异，特别是在白垩纪。在拟议的项目中，这些展开的菊石将分析其形态空间的占领，使用相关的字符，如海螺几何形状，壳的取向，和缝合线。选择分类群（取决于材料的可用性）从白垩纪将进行研究，包括可能的两性异形，种内变异，个体发育性状的变化。它们的地理分布广泛、丰度高、进化速度快，以及由于增生外壳生长而保存了整个个体发育过程，使它们成为研究古生态扰动进化情景的完美化石群。该项目的主要目的是（1）检验白垩纪异形菊石起源的各种假设，（2）评估种和属的概念以及高级分类实体的有效性及其系统发育关系，（3）调查古生态参数及其对海螺几何形状的可能影响，（4）比较个体发育特征的多样性和差异模式。本文首次尝试分析了白垩纪异形菊石的种内变异性，并讨论了它们与单形菊石在卷曲和螺形方面的差异。通过这项研究，我们将提高对白垩纪展开菊石的系统发育关系、古生物学、古生态学和地层范围的理解。白垩纪时期的特点是海侵/海退，变暖/冷却事件和海洋缺氧事件，这使得它非常适合研究的外观和分布的特定异形壳形态，并希望检测到的特征模式。与同期沉积物中正常盘绕的菊石相比，可以测试不同的古环境变化（水深，温度，氧气）及其对异形壳几何形状的影响。

项目成果

Traumatic events in the life of the deep-sea cephalopod mollusc, the coleoid Spirula spirula

深海头足类软体动物（鞘状螺旋体）生命中的创伤事件

• DOI: 10.1016/j.dsr.2018.10.007
• 发表时间: 2018
• 期刊: Deep Sea Research Part I: Oceanographic Research Papers
• 作者: René Hoffmann;Robert E. Lemanis;Lena Wulff;Stefan Zachow;Alexander Lukeneder;Christian Klug;Helmut Keupp
• 通讯作者: Helmut Keupp

Morphological disparity and ontogeny of the endemic heteromorph ammonite genus Aegocrioceras (Early Cretaceous, Hauterivian, NW-Germany)

• DOI: 10.1016/j.palaeo.2019.01.020
• 发表时间: 2019-04-15
• 期刊: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
• 影响因子: 3
• 作者: Hoffmann, Rene;Weinkauf, Manuel F. G.;De Baets, Kenneth
• 通讯作者: De Baets, Kenneth