A hidden record of early animal evolution? Exploring the Cambrian diversity of acritarchs and small carbonaceous fossils.

早期动物进化的隐藏记录？

• 批准号: 2734191
• 金额: --
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2734191
• 关键词: hidden; record; early; animal; evolution

Overview: Microfossils offer a rich record of early animal evolution and the attendant reconfiguring of ecosystems. This project will focus on exceptionally well-preserved acritarchs and small carbonaceous fossils (SCFs) to reach a new understanding of how animals dramatically changed the biosphere around half a billion years ago, in the Cambrian evolutionary 'explosion'. The project aims to discriminate between animal- and non-animal microfossils, and constrain their biological affinities, modes of life, and distributions in space and time. The results will bring key insights into changes in diversity and ecology through a pivotal interval in Earth history.Acritarchs are organic-walled microfossils of unknown affinity, extracted using standard palynological laboratory techniques. In contrast, more gentle procedures yield larger, more delicate SCFs that represent a range of organisms, including a diversity of animals. Despite this categorization, the two datasets overlap. Recently, we have begun to explore a combined approach, which promises to shed light on the affinities and significance of both acritarchs and SCFs, enhancing their application to key questions in palaeobiology, stratigraphy, and ancient ecosystems. The project will focus initially on exceptionally well-preserved acritarchs and SCFs from the Forteau Formation of Newfoundland, Canada (Cambrian Stage 4, c. 510 million years ago). Hundreds of SCFs and thousands of acritarchs have already been prepared onto glass slides for analysis. In light of the SCFs, some palynomorphs are clearly derived from animals including arthropods, priapulid worms, and the slug-like Wiwaxia. Others remain enigmatic, such as the conical acritarchs known as Ceratophyton and Corollasphaeridium, which could represent animals or perhaps protists. At the same time, SCF-processing yields clumps, articulated arrays, and even faecal-pellets full of acritarchs, constraining their biological interpretation. Therefore, the Forteau material offers an unrivalled opportunity to resolve the affinities and ecologies of otherwise mysterious Cambrian microfossils. Any insights can then be applied more widely to help constrain the largest-scale patterns and processes of the Cambrian 'explosion'. For example, do animal-derived microfossils extend back into the Ediacaran? Can acritarchs tell us about the structure of the plankton? And how did ecosystems respond to major events in evolution? Figure 1: Selection of lower Cambrian microfossils, each measuring around 20 to 40 microns in size; they include two spiny acritarchs alongside conical and spine-tipped forms that could represent unicellular protists or animal body parts.

概述：微化石提供了早期动物进化的丰富记录和随之而来的生态系统的重新配置。该项目将集中于保存完好的杂质和小型化石（SCFS），以对动物如何在寒武纪进化的“爆炸”中对动物的生物圈进行巨大改变。该项目旨在区分动物和非动物微化石，并限制其生物学亲和力，生活方式和时空中的分布。结果将通过在地球历史上的关键间隔来对多样性和生态学的变化产生关键的见解。含义是使用标准的元水学实验室技术提取的未知亲和力的有机壁微化石。相比之下，更温和的程序产生了更大，更精致的SCF，这些SCF代表了一系列生物，包括多种动物。尽管进行了分类，但两个数据集重叠。最近，我们开始探索一种联合方法，该方法有望阐明Acritarchs和SCF的亲和力和意义，从而增强了它们对古生物学，地层学和古代生态系统中关键问题的应用。该项目最初将重点放在加拿大纽芬兰的Forteau组（Cambrian Stage 4，5.1亿年前）的特殊保存完好的Acritarchs和SCF上。已经在载玻片上准备了数百个SCF和数千个Acritarch，以进行分析。鉴于SCF，一些palynomorphs明显源自包括节肢动物，priapulid蠕虫和sl弹状的Wiwaxia在内的动物。其他人仍然保持神秘状态，例如称为Ceratophyton和Corollasphaeridium的圆锥形Acritarch，它们可以代表动物或生物。同时，SCF处理产生了团块，铰接的阵列，甚至充满了充满Acritarchs的粪便，从而限制了它们的生物学解释。因此，Forteau材料提供了一个无与伦比的机会，可以解决原本神秘的寒武纪微化石的亲和力和生态。然后，任何见解都可以更广泛地应用，以帮助限制寒武纪“爆炸”的最大规模模式和过程。例如，动物衍生的微化石会延伸到埃迪亚达（Ediacaran）吗？ Acritarchs可以告诉我们浮游生物的结构吗？生态系统如何应对进化中的重大事件？图1：下寒武纪微化石的选择，每个化石的大小约为20至40微米；它们包括两种刺刺的Acritarchs，以及可以代表单细胞生物或动物身体部位的圆锥形和脊柱尖头的形式。