Department of Behavioral Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
Department of Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
Philos Trans A Math Phys Eng Sci. 2022 Sep 19;380(2232):20210335. doi: 10.1098/rsta.2021.0335. Epub 2022 Aug 1.
Most molluscan taxa forage with their radula, a chitinous membrane with embedded teeth. The teeth are the actual interfaces between the animal and its ingesta and serve as load-transmitting regions. During foraging, these structures have to withstand high stresses without structural failure and without a high degree of wear. Mechanisms contributing to this failure- and wear-resistance were well studied in the heavily mineralized teeth of Polyplacophora and Patellogastropoda, but for the rather chitinous teeth of non-limpet snails, we are confronted with a large gap in data. The work presented here on the paludomid gastropod aims to shed some light on radular tooth composition and its contribution to failure- and wear-prevention in this type of radula. The teeth were fractured and the micro-cracks studied in detail by scanning electron microscopy, revealing layers within the teeth. Two layers of distinct fibre densities and orientations were detected, covered by a thin layer containing high proportions of calcium and silicon, as determined by elemental dispersive X-ray spectroscopy. Our results clearly demonstrate the presence of failure- and wear-prevention mechanisms in snail radulae without the involvement of heavy mineralization-rendering this an example of a highly functional biological lightweight structure. This article is part of the theme issue 'Nanocracks in nature and industry'.
大多数软体动物类群用齿舌（齿舌是一种带有嵌入牙齿的几丁质膜）来觅食。这些牙齿是动物与其食物之间的实际界面，它们充当着传递负载的区域。在觅食过程中，这些结构必须在不发生结构故障和高磨损的情况下承受高应力。在富含矿物质的多板纲和腹足纲牙齿中，对促成这种抗断裂和抗磨损的机制进行了很好的研究，但对于相对来说几丁质化的无帽贝型蜗牛的牙齿，我们的数据存在很大的差距。这里介绍的关于滨螺目腹足动物的工作旨在阐明齿舌牙齿的组成及其在这种类型的齿舌中对预防断裂和磨损的贡献。通过扫描电子显微镜对断裂的牙齿和微裂纹进行了详细研究，揭示了牙齿内部的分层。检测到两个具有明显纤维密度和取向的层，由一层含有高比例钙和硅的薄层覆盖，这是通过元素分散 X 射线光谱确定的。我们的研究结果清楚地表明，在没有重矿化参与的情况下，蜗牛齿舌中存在抗断裂和抗磨损的机制，这是高度功能化的生物轻质结构的一个例子。本文是“自然界和工业中的纳米裂纹”主题特刊的一部分。
