Data from: Microwear-mesowear congruence and mortality bias in rhinoceros mass death assemblages

Although we do not know the cause of death of most fossils, mortality is often associated with ecological stress due to seasonality and other stochastic events (storms, volcanism) that may have caused shifts in feeding ecology preceding death. In these instances, dental microwear, which reflects feeding ecology in a narrow window of time, may provide a biased view of diet. Mesowear, another dental wear proxy based on the morphology of worn cusps, requires macroscopic amounts of dental wear and reflects diet for a longer interval and may be less prone to bias from near-death ecological stress. We compared congruence between microwear and mesowear of North American fossil rhinocerotid mass death assemblages and hunted collections of modern rhinocerotids to test the hypothesis that fossil assemblages yield more incongruous microwear and mesowear results as a result of near-death ecological disturbances. In extant rhinos, both microwear and mesowear are associated with diet and height of the feeding environment. Mesowear and microwear in the modern rhinocerotid collections are statistically correlated with strong relationships between average mesowear scores and labially distributed dental microwear. In contrast, a statistical relationship between mesowear and microwear was not observed among the fossil rhinocerotid assemblages. Mesowear suggests the fossil rhinos had low abrasion diets, suggesting they fed from clean, possibly tall vegetation. Some, but not all mass death assemblages produce microwear data with excessive scratches and/or pits compared to expectations based on mesowear results, suggesting that dental microwear was altered shortly before death in some but not all of the fossil assemblages. The dental wear proxies available to paleoecologists provide a mosaic of dietary evidence reflecting diet over long (mesowear) and more abbreviated (microwear) periods of time that, together, provide a richer understanding of feeding ecology and its relationship to environment, seasonal change, and other ecological disturbances.尽管多数化石物种的致死原因尚未明确，但死亡事件往往与季节性波动及其他随机事件（风暴、火山活动）引发的生态胁迫相关——这类胁迫可能在个体死亡前改变其取食生态。牙齿微磨耗（dental microwear）仅能反映极短时间窗口内的取食生态，因此可能对其饮食情况给出有偏的推断。而牙齿宏观磨耗（mesowear）是另一种基于磨损牙尖形态的牙齿磨损代用指标，需要达到一定规模的牙齿磨损量，可反映更长时间段内的饮食状况，且不易受死亡前短期生态胁迫的干扰。本研究对比了北美化石犀科（rhinocerotid）集群死亡埋藏群（mass death assemblages）的牙齿微磨耗与宏观磨耗一致性，并以现代犀科动物的狩猎馆藏标本作为对照，以此验证如下假说：由于死亡前的生态扰动，化石埋藏群的微磨耗与宏观磨耗结果往往更不一致。在现生犀牛中，牙齿微磨耗与宏观磨耗均与饮食类型及取食环境高度相关。现代犀科馆藏标本的宏观磨耗平均得分与唇侧分布的牙齿微磨耗特征间存在显著的统计学相关性。与之形成鲜明对比的是，在化石犀科埋藏群中并未观察到宏观磨耗与微磨耗间的统计学关联。牙齿宏观磨耗结果显示，这些化石犀牛的饮食磨损率较低，表明它们取食相对洁净、可能较高的植被。部分（而非全部）集群死亡埋藏群的微磨耗数据显示，其划痕与/或凹陷数量超出了基于宏观磨耗结果的预期，这表明在部分（而非全部）化石埋藏群中，牙齿微磨耗在个体死亡前不久发生了改变。古生态学家可利用的各类牙齿磨损代用指标，共同构成了一套覆盖不同时间尺度的饮食证据组合——长期尺度为牙齿宏观磨耗，短期尺度为牙齿微磨耗。借助这套证据组合，我们能够更全面地理解取食生态及其与环境、季节变化及其他生态扰动之间的关联。