Collaborative Proposal: Dental Development and Life History of Malagasy Lemurs

合作提案：马达加斯加狐猴的牙齿发育和生活史

• 批准号: 0503988
• 负责人: Gary Schwartz
• 金额: $ 6.56万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-16 至 2007-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0503988&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Dental; Development; Life

Ever since the pioneering work of Adolf Schultz, primatologists have shown a sustained interest in the skeletal developmental correlates of life history variation among primates, and in their implications for understanding the evolution of life history. More recently, the fossil record has been the direct focus of such comparative work. New tools in dental microstructure are available for teasing out aspects of life history variation among extinct species and have begun to be applied with great success to subfossil lemurs. Teeth preserve within them a permanent record of their development enabling researchers to retrieve longitudinal developmental data from single adult specimens. This is not merely extremely useful for exploring life history variation among extinct species, but it promises to revolutionize our understanding of some aspects of the life histories of extant species as well. Scientific merit: This study will bring the study of dental microstructure and other new analytical tools to bear on one of the most fascinating groups of extinct primates: the giant subfossil lemurs of Madagascar. Their closest living relatives, the extant lemurs, show remarkable variation in the timing of dental, craniofacial, and somatic growth and development, all within the context of a highly seasonal and unpredictable environments. These differing patterns of dental and skeletal growth relate to variation in lemur life history strategies - in particular, to the trade-off between adult female survival and reproductive effort. By combining data on the behavioral ontogeny of food processing (using new techniques in use-wear analyses), dental development and eruption (via radiography), and dental microstructural analyses of single adult specimens, this project will address questions never before asked of extinct primates: How long was gestation in giant lemurs? How rapidly did they grow? At what age did weaning occur in these species, and how prolonged was the weaning transition? Do frugivorous lemur species grow more slowly than like-sized folivores, as predicted by the ecological risk aversion hypothesis? Does the seasonal scheduling of growth in extinct lemurs cause a large proportion of adult size to be achieved before weaning, or do fundamentally different rates of infant growth characterize extinct lemur taxa as they do extant lemurs? Finally, advances in landmark-based 3-D geometric morphometrics (e.g., Morphologika, HETPAD), along with conventional analysis of trait-age matrices to chronicle the relationships between dental, brain and craniofacial development in extinct lemurs, allows us to test current hypotheses regarding the evolution of life history strategies in what is perhaps the world's most unique and diverse adaptive radiation of primates. Ultimately, this study will provide the evolutionary developmental framework for understanding the evolution of life history variation in primates. Broader impact: An important broader impact of this study is graduate and postgraduate training. One of the PIs has a Malagasy graduate student who is studying lemurs and has expressed an interest in learning the techniques described here. The microstructural work required here will also provide ideal training for a two-year postdoctoral associate. Furthermore, the PIs have ongoing collaborations with others in the realms of Madagascar's paleobiology, lemur ecology, ecomorphology, heterochrony and skeletal ontogeny, and dental microstructure. We expect the work described here to intersect profitably with other research projects, and thus to inform research on the evolution of primate community structure in Madagascar, the patterns and causes of extinction, and the evolutionary developmental biology of primates.

自从阿道夫·舒尔茨（Adolf Schultz）的开创性工作以来，灵长类动物学家对灵长类动物生活史变异的骨骼发育相关性及其对理解生活史进化的意义表现出持续的兴趣。最近，化石记录一直是这种比较工作的直接焦点。牙齿显微结构的新工具可用于梳理灭绝物种之间生活史变化的各个方面，并已开始应用于亚化石狐猴，并取得了巨大成功。牙齿保存在他们的发展，使研究人员能够从单个成人标本检索纵向发展数据的永久记录。这不仅对探索灭绝物种的生活史变异非常有用，而且它也有望彻底改变我们对现存物种生活史某些方面的理解。科学价值：这项研究将把牙齿显微结构和其他新的分析工具的研究，以承担最迷人的灭绝灵长类动物群体之一：马达加斯加的巨大亚化石狐猴。它们的近亲，现存的狐猴，在牙齿、颅面和躯体生长和发育的时间上表现出显着的变化，所有这些都是在高度季节性和不可预测的环境中。这些不同的牙齿和骨骼生长模式与狐猴生活史策略的变化有关-特别是成年雌性生存和生殖努力之间的权衡。通过结合食物加工的行为个体发育（使用使用磨损分析中的新技术），牙齿发育和萌出（通过放射照相术）以及单个成年标本的牙齿显微结构分析的数据，该项目将解决灭绝灵长类动物从未被问过的问题：巨型狐猴的妊娠期有多长？他们成长得有多快？在这些物种中，断奶发生在什么年龄，断奶过渡期有多长？食果狐猴物种比同样大小的食叶动物生长得更慢，正如生态风险厌恶假说所预测的那样吗？灭绝狐猴的季节性生长时间表是否会导致大部分成年大小在断奶前达到，或者婴儿生长速度的根本不同是灭绝狐猴分类群与现存狐猴的特征吗？最后，基于地标的3-D几何形态测量学的进展（例如，Morphologika，HETPAD），沿着传统的特征年龄矩阵分析来记录已灭绝狐猴牙齿、大脑和颅面发育之间的关系，使我们能够测试目前关于生活史策略进化的假设，这可能是世界上最独特和最多样化的灵长类适应性辐射。最终，本研究将为理解灵长类动物生活史变异的进化提供进化发展框架。更广泛的影响：这项研究的一个重要的更广泛的影响是研究生和研究生培训。其中一个PI有一个马达加斯加研究生，他正在研究狐猴，并表示有兴趣学习这里描述的技术。这里所需的微观结构工作还将为为期两年的博士后助理提供理想的培训。此外，PI与马达加斯加的古生物学，狐猴生态学，生态形态学，异时性和骨骼个体发育以及牙齿微观结构等领域的其他人正在进行合作。我们希望这里描述的工作与其他研究项目有着有益的交叉，从而为马达加斯加灵长类动物群落结构的演变、灭绝的模式和原因以及灵长类动物的进化发育生物学研究提供信息。