Environmental and biotic controls on conodont body size and teeth morphology as proxies for their feeding ecology

在有颌脊椎动物出现之前，牙形刺是古生代早期海洋中数量最多、种类最多的掠食者。磷化齿在上寒武纪至三叠纪海相岩石中大量存在。由于其异常快速的形态演变，牙形刺被确立为生物地层学的主要工具。然而，使这种食品加工结构快速多样化的喂养生态仍然未知。该项目的核心问题是：牙形石的形态如何反映它们的营养位置、饮食和环境条件？该项目将开发定量代理来研究牙形石牙齿，并提供其在非生物环境（岩相）和生物相互作用（群落结构）中的功能变异性模型。牙齿大小将被量化作为猎物大小的代理，生物矿化组织的厚度将被用作硬噬的指标。这些参数将在瑞典哥特兰岛中志留纪碳酸盐演为的环境梯度中进行检查。该项目将允许从微观进化模式中区分生态表型变异。它还将通过测试从其他动物群中获得的生态模型（例如，群落中体型结构与营养链长度之间的关系）来确定这种可变性的关键控制因素。这些模型将通过应用地球化学指标对单个生物的营养水平进行独立测试。该项目将提供一个框架，在该框架内，牙形石形态多样性可以通过将其划分为生态表型和进化趋势来解释。

Before the advent of jawed vertebrates, conodonts were the most abundant and diverse predators of early Palaeozoic oceans. Their phosphatic teeth abound in upper Cambrian through Triassic marine rocks. Thanks to their extraordinarily rapid morphological evolution, conodonts are established as a prime tool in biostratigraphy. Yet the feeding ecology that allowed this rapid diversification of food-processing structures remains unknown.The core question of this project is: How does conodont morphology reflect their trophic position, diet, and environmental conditions? This project will develop quantitative proxies to study conodont teeth and provide models of their variability in function of the abiotic environment (lithofacies) and biotic interactions (community structure). Teeth size will be quantified as a proxy for prey size, and thickness of the biomineralized tissue will be used as an indicator of durophagy. These parameters will be examined across well-documented environmental gradients in the middle Silurian carbonate succession of Gotland, Sweden. The project will allow distinguishing ecophenotypic variability from microevolutionary patterns. It will also identify the key controls on this variability by testing ecological models derived from other faunal groups, e.g. the relationship between body size structure in a community and the length of the trophic chain. These models will be independently tested by applying geochemical proxies for the trophic level of individual organisms. The project will provide a framework within which conodont morphological diversity across geological successions can be interpreted by partitioning it into ecophenotypic and evolutionary trends.