Abstract Sharks are apex-predators that play an important role in past and present aquatic food webs. However, their diet - especially in extinct species - is often not well constrained. Dental microwear texture analysis (DMTA) has been successfully applied to reconstruct diet and feeding behaviours of different aquatic and terrestrial vertebrates. However, unlike in mammals, food-to-tooth contact in sharks is rather limited because only larger prey is manipulated before swallowing. Together with a fast tooth replacement rate, this reduces wear on individual teeth. Here, we present an explorative study of dental microwear texture on extant and extinct sharks to test whether ante-mortem wear is related to ingested diet or habitat preferences and resistant to post-mortem alteration processes. Shark teeth from 24 modern species and 12 fossil species from different localities were measured. As an additional comparison, extant shark teeth of Carcharhinus plumbeus were tumbled in sediment-water suspensions to simulate post-mortem mechanical alteration by sediment transport. Only three of the twelve extant shark species with three or more specimens had significantly different dental surface textures. Furthermore, no clear relation between food or habitat preferences and ante-mortem dental wear features was detected for this sample set. Tumbling modern shark teeth with siliciclastic sediment of four different grain size fractions led to increasing complexity of the dental surface. Fossil specimens resemble these experimentally altered shark teeth more in complexity and roughness. Thus, fossil shark teeth seem to display either very different (e.g. harder) diet-related wear or a strong degree of post-mortem alteration. Based on our restricted sample size, dental wear of shark teeth does overall not seem to simply reflect dietary differences; hence, it is difficult to use DMTA as reliable dietary reconstruction, in either extant nor extinct sharks.

中文翻译：

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现存和灭绝鲨鱼的牙齿微磨损纹理分析：死前或死后牙齿磨损？

摘要 鲨鱼是顶级捕食者，在过去和现在的水生食物网中都发挥着重要作用。然而，它们的饮食——尤其是在已灭绝的物种中——通常没有受到很好的限制。牙科微磨损纹理分析 (DMTA) 已成功应用于重建不同水生和陆生脊椎动物的饮食和摄食行为。然而，与哺乳动物不同的是，鲨鱼的食物与牙齿的接触相当有限，因为只有更大的猎物在吞咽之前才会被操纵。加上快速的牙齿更换率，这减少了单个牙齿的磨损。在这里，我们对现存和已灭绝鲨鱼的牙齿微磨损纹理进行了探索性研究，以测试死前磨损是否与摄入的饮食或栖息地偏好有关，以及对死后改变过程的抵抗力。测量了来自不同地区的 24 种现代物种和 12 种化石物种的鲨鱼牙齿。作为额外的比较，在沉积物 - 水悬浮液中翻滚 Carcharhinus pumpeus 现存的鲨鱼牙齿，以模拟沉积物运输造成的死后机械改变。拥有三个或更多标本的 12 种现存鲨鱼中，只有 3 种具有显着不同的牙齿表面纹理。此外，对于该样本集，未检测到食物或栖息地偏好与死前牙齿磨损特征之间的明确关系。用四种不同粒度的硅质碎屑沉积物翻滚现代鲨鱼牙齿导致牙齿表面的复杂性增加。化石标本在复杂性和粗糙度上更类似于这些经过实验改造的鲨鱼牙齿。因此，鲨鱼化石牙齿似乎显示出与饮食相关的非常不同（例如更硬）的磨损或强烈程度的死后改变。根据我们有限的样本量，鲨鱼牙齿的牙齿磨损总体上似乎并不能简单地反映饮食差异；因此，无论是现存的还是已灭绝的鲨鱼，都很难将 DMTA 用作可靠的饮食重建。