ROW: Trophic Diversity in Ancient and Modern Predator Guilds: An Ecomorphological Analysis

对化石群落的研究可以为生态学家和古生物学家提供很多东西。化石记录可以提供未受人类影响的群落，在一个时间尺度上记录历史进程的影响，如灭绝和移民，对群落结构的影响。在过去的3700万年里，北美大型陆地哺乳动物捕食者协会的营养多样性将被探索。这些古行会的年龄在200万年到400万年之间，它们将随着时间的推移与之前分析过的四个近代行会样本进行比较。采样的古动物包括一些在大灭绝事件之前或之后的动物，还有一些没有像猫和鬣狗这样典型的现代食肉动物。利用生态形态学方法，营养多样性将通过体型和先前证明的动物牙齿的功能测量来评估。测量包括对切片、研磨和碎骨能力的估计，并反映饮食中肉、骨和非脊椎动物食物的相对比例。主成分分析将应用于这些数据，以创建一个多变量形态空间，在其中查看行会内物种的分布。用分类群之间的欧几里得距离来衡量的物种堆积，将与假设的、随机产生的行会进行比较。此外，将量化每个时间段的猎物种类数量和体型分布，以探索资源特征对种群组成的影响。如果存在捕食者行会结构的一般规则，那么这些结果将可能对群落生态学产生广泛的影响。

The study of fossil comunities has much to offer ecologists, as well as paleontologists. The fossil record can provide communities undisturbed by human influence over a time scale that chronicles the influence of historical processes, such as extinction and immigration, on community structure. Trophic diversity within the guild of large, terrestrial mammalian predators in North America over the last 37 million years will be explored. The paleoguilds, separated in age by two to four million years, will be compared over time to a sample of four previously analyzed Recent guilds. The sampled paleofaunas include some which precede or follow mass extinction events, and some that are missing such typical modern carnivores as cats and hyaenas. Using an ecomorphological approach, trophic diversity will be assessed by body size and previously demonstrated, functional measurements of canivore teeth. Measurements include estimates of slicing, grinding and bone-crushing abilities and reflect the relative proportion of meat, bone, and non-vertebrate foods in the diet. A principal component analysis will be applied to these data to create a multivariate morphospace in which to view the distribution of species within guilds. Species packing, as measured by Euclidean distance between taxa, will be compared among guilds with hypothetical, randomly generated guilds. In addition, the number and body size distribution of prey species will be quantified for each time period to explore the influence of resource characteristics on guild composition. Results should suggest general rules, if they exist, of predator guild structure that are likely to have broad implications for community ecology.