DISSERTATION RESEARCH: MARINE MAMMAL FEEDING GUILDS: DIVERSITY ANDOVERTURN THROUGH THE CENOZOIC

论文研究：海洋哺乳动物喂养行会：多样性和颠覆通过CenosicicBlaire Van Valkenburgh和Peter J.Adam加州大学洛杉矶分校海洋哺乳动物构成了一组不相关的动物，对海洋资源具有强制性的依赖。食肉海洋哺乳动物包括鲸目动物(鲸鱼和海豚)、鳍脚类动物(海豹和海狮)和海獭。在这些群体中有各种各样的摄食策略，可以根据头骨和牙齿的功能特征来区分，以及预测捕食者和猎物身体大小之间的比例关系的模型。这个项目将记录过去5000万年来海洋哺乳动物的摄食类型和身体大小的多样性，并推断本地和全球海洋哺乳动物群落内部和之间的竞争和替换的发生率。活的和化石的海洋哺乳动物的时空分布将通过文献和对博物馆藏品的调查来确定。根据头骨和牙齿的功能特征，化石分类群将被归类为现代海洋哺乳动物中观察到的四种广泛的摄食策略之一。这些策略包括咀嚼(如海獭)、刺穿(如大多数海豚)、吸食(如海象)和滤食(如须鲸)。在每项战略中，化石类群的摄食制度将进一步分解为更具描述性的亚类(例如，中上层捕食鱿鱼的吸食者与捕食底栖双壳类的吸食者)。还将开发预测化石分类群中身体大小的方法，并将其应用于捕食者模型：猎物身体大小关系，以确定海洋哺乳动物化石可能采取的猎物大小。分布和多样性数据将进一步解释与新生代挖掘学(保存性)偏差和重大古海洋事件有关的数据。不同海洋哺乳动物种群之间和内部的摄食策略的周转和趋同模式将揭示争夺食物资源及其影响的情况。综上所述，这些数据将有助于更好地了解充满活力的新生代海洋群落。这项研究是对新生代海洋脊椎动物群落的首次全面检查。虽然化石分类群中的取食策略的解释是一种常见的做法，但在更广泛的古生态意义上解释这些数据的情况很少。这项研究不仅提供了海洋哺乳动物随时间的生态作用的全面总结，还提供了一个框架，可以从这个框架来解释其他大型海洋捕食者(如鲨鱼、鱿鱼)的生态作用。所有数据都将在公共领域存档，供其他研究人员使用。调查人员将根据这一研究项目，为洛杉矶市区表现不佳的高中开展本科生研究项目和活动。

Dissertation Research: Marine Mammal Feeding Guilds: Diversity and Overturn Through the CenozoicBlaire Van Valkenburgh and Peter J. AdamUniversity of California, Los AngelesMarine mammals constitute a diverse and unrelated assemblage of animals with an obligate dependence on marine resources. Carnivorous marine mammals include cetaceans (whales and dolphins), pinnipeds (seals and sea lions), and sea otters. Within these groups are a wide variety of feeding strategies that can be distinguished based on functional characters of the skull and teeth as well as models that predict scaling relationships between predator and prey body sizes. This project will document the diversity of feeding types and body sizes in marine mammals over the past 50 million years, and infer incidence of competition and replacement within and between marine mammal communities at both local and global scales.Temporal and spatial distributions of living and fossil marine mammals will be determined from the literature and a survey of museum collections. Fossil taxa will be categorized into one of four broad feeding strategies observed in modern marine mammals based on functional skull and tooth characteristics. These strategies include masticatory (e.g., sea otters), piercing (e.g., most dolphins), suction (e.g., walrus), and filter feeding (e.g., baleen whales). Within each strategy, feeding regimes of fossil taxa will be further resolved into more descriptive subcategories (e.g., pelagic squid-eating suction feeders versus benthic bivalve-eating suction feeders). Methods for predicting body size in fossil taxa will also be developed and applied to models of predator:prey body size relationships to establish probable prey sizes taken by fossil marine mammals. Distribution and diversity data will be further interpreted in relation to taphonomic (preservational) biases and major paleoceanographic events of the Cenozoic. Patterns of turnover and convergence in feeding strategies among and within various marine mammal lineages will reveal cases of competition for food resources and its effects. Taken together, these data will contribute to a much better understanding of dynamic Cenozoic marine communities. This study is the first comprehensive examination of any Cenozoic marine vertebrate community. Although interpretation of feeding strategies in fossil taxa is a common practice, interpretation of these data in a broader paleoecological sense is rarely realized. This study not only provides a comprehensive summary of ecological roles of marine mammals through time; it also provides a framework from which ecological roles of other large marine predators (e.g., sharks, squid) can be interpreted. All data will be archived in the public domain for use by other researchers. The investigators will develop undergraduate research projects and activities for under-performing high schools in urban Los Angeles based on this research project.