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

论文研究：海洋哺乳动物喂养协会：多样性和推翻通过新生代。blaire Van Valkenburgh和Peter J. adams加利福尼亚大学洛杉矶分校海洋哺乳动物构成了一个多样化和不相关的动物组合，对海洋资源有义务的依赖。食肉性海洋哺乳动物包括鲸目动物（鲸鱼和海豚）、鳍足动物（海豹和海狮）和海獭。在这些群体中有各种各样的捕食策略，可以根据头骨和牙齿的功能特征以及预测捕食者和猎物身体大小之间的比例关系的模型来区分。该项目将记录过去5000万年中海洋哺乳动物摄食类型和体型的多样性，并推断当地和全球范围内海洋哺乳动物群落内部和之间的竞争和替代发生率。活的和化石的海洋哺乳动物的时空分布将确定从文献和博物馆收藏的调查。化石分类群将根据颅骨和牙齿的功能特征，将现代海洋哺乳动物分为四种广泛的进食策略之一。这些策略包括咀嚼（如海獭）、穿刺（如大多数海豚）、吸力（如海象）和滤食（如须鲸）。在每种策略中，化石类群的摄食机制将进一步分解为更具描述性的子类别（例如，远洋吸食乌贼与底栖双壳类吸食动物）。预测化石类群体型的方法也将被开发，并应用于捕食者：猎物体型关系的模型，以建立化石海洋哺乳动物可能的猎物体型。分布和多样性数据将进一步解释与地学（保存）偏差和新生代主要古海洋学事件有关的数据。在不同的海洋哺乳动物谱系之间和内部，喂养策略的更替和趋同模式将揭示食物资源竞争的情况及其影响。综合起来，这些数据将有助于更好地了解动态的新生代海洋群落。这项研究是首次对新生代海洋脊椎动物群落进行全面研究。虽然解释化石分类群的摄食策略是一种常见的做法，但从更广泛的古生态意义上解释这些数据却很少实现。这项研究不仅全面总结了海洋哺乳动物的生态作用；它还提供了一个框架，从其他大型海洋捕食者（如鲨鱼，鱿鱼）的生态作用可以解释。所有的数据将被存档在公共领域供其他研究人员使用。研究人员将在此研究项目的基础上，为洛杉矶市区表现不佳的高中开发本科研究项目和活动。

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.