Dietary signals in dental microwear of predatory small mammals appear unaffected by extremes in environmental abrasive load
Dietary signals in dental microwear of predatory small mammals appear unaffected by extremes in environmental abrasive load
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DOI：
10.1016/j.palaeo.2020.109929
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发表时间：
2020-11-15
影响因子：
3
通讯作者：
Purnell, Mark A.
中科院分区：
文献类型：
--
作者：
Adams, Neil F.;Gray, Thomas;Purnell, Mark A.
牙齿微磨损纹理分析(DMTA)是重建现存和灭绝动物饮食结构的关键指标。牙齿磨损的原因几十年来一直存在争议，但最近有争议的观点认为，环境中的外源磨料(或砂粒)对微磨损形成的影响比食品更大，这重新引起了人们对这一研究领域的兴趣。使用大型哺乳动物进行的喂养试验表明，尽管颗粒负荷不同，DMTA仍然可以区分饮食差异。然而，外源磨料对具有定量磨粒负荷的小型非食草性哺乳动物的牙齿微磨损的影响仍未得到测试。在这里，我们研究了来自欧洲鼹鼠(Talpa Europaea)的牙齿微磨损纹理，这为砂砾的作用提供了一个理想的测试，因为鼹鼠的地下栖息地和以蚯蚓为主的食物中含有外源磨料，并被外源磨料覆盖。我们量化了来自英国诺福克的鼹鼠的环境磨料负荷(通过测量土壤的硅酸盐含量)和膳食磨料负荷(通过测量胃内容物的硅酸盐含量)，以评估砂砾负荷的变化对微磨料质地的影响。微磨损质地参数与外生磨粒载荷的任何量度之间，或质地参数与土壤物理磨粒特性之间没有显著的关系。将鼹鼠的微磨损纹理与蝙蝠的微磨损纹理进行比较，发现鼹鼠的微磨损纹理在多元质地-饮食空间上与蝙蝠食用软的猎物没有什么区别，支持这样的说法，即微磨损纹理保留了准确的饮食特征，不会被外来磨料的磨损所覆盖。借鉴侏罗纪哺乳动物的例子，我们论证了这些结果对重建哺乳动物化石的饮食和习性的影响。
Dental microwear texture analysis (DMTA) is a key proxy used to reconstruct the diets of extant and extinct animals. Causal agents of dental wear have been debated for decades, but the recent controversial suggestion that exogenous abrasives (or 'grit' particles) from the environment exert a greater influence on microwear formation than food items has led to renewed interest in this field of research. Feeding trials using large mammals suggest that DMTA can distinguish dietary differences despite variable grit loads. However, the effect of exogenous abrasives on the dental microwear of small, non-herbivorous mammals with quantified grit loads remains untested. Here, we examine dental microwear textures from the European mole (Talpa europaea), which provides an ideal test for the role of grit given moles' subterranean habitat and diet dominated by earthworms that contain, and are coated by, exogenous abrasives. We quantify the environmental abrasive load (by measuring silicate content of soils) and dietary abrasive load (by measuring silicate content of stomach contents) for moles from sites across Norfolk, UK to evaluate the effect of variation in grit loads on microwear textures. No significant relationships are found between microwear texture parameters and any metric of exogenous abrasive load, or between texture parameters and physical soil grit characteristics. Comparing mole microwear textures with those of bats, which have negligible environmental abrasive loads, reveals that moles are indistinguishable in multivariate texture-dietary space from bats that consume 'soft' prey, supporting suggestions that microwear textures preserve accurate dietary signatures and are not overwritten by wear from exogenous abrasives. Drawing upon examples from Jurassic mammaliaforms, we demonstrate the implications of these results for reconstructing the diets and habits of fossil mammals.