Doctoral Dissertation Improvement: Extant Island Dwarf Mammals as Models for Insular Dwarfing in Pleistocene Hominids

博士论文改进：现存岛屿矮哺乳动物作为更新世原始人类岛屿矮化的模型

• 批准号: 0824583
• 负责人: Joan Richtsmeier
• 金额: $ 1.5万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0824583&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Improvement; Extant; Island

Derived, species-level reduction in body size (dwarfing) of isolated populations has occurred in many mammals and may have even affected some of our hominid relatives. Common postcranial correlates of island dwarfing have been documented, yet there are few detailed studies of how the form of the skull and its many integrated components are affected. This project will examine museum specimens of several island species that have reduced body size compared to their ancestors in order to characterize differences in size and shape of the skull. Craniofacial morphology of several endemic primate species will be quantified using multiple size and shape metrics, including methods from 3D geometric morphometrics, and compared to closely-related mainland primates. Regression analyses will account for phylogeny when appropriate. In addition, an example of island dwarfing in carnivores will provide a non-primate comparative case. The aims of these interspecies comparisons are threefold. First, the study will define the changes in craniofacial form associated with island dwarfing in a sample of extant primate species. Second, it will identify any commonalities among the island dwarf populations relative to their mainland counterparts by testing for differences in shape, size, and degree of encephalization. The null hypothesis in each case will be the allometrically-predicted condition (for a given body size) based on previous studies of the taxonomic group in question. Finally, the project will use the findings of aims 1 and 2 to shed light on the interpretation of the Flores hominid remains exhibiting apparently unexpected craniofacial proportions. The quantitative characterization of skull shape in known cases of island dwarfing will lend needed insight into the mechanisms of this process and its possible effects on an extinct member of the hominid lineage.Although evolutionary oddities such as dwarf mammoths and giant rodents have always interested researchers, they have recently risen to prominence since the remains of a small-bodied, small-brained human were recovered on the island of Flores in Indonesia. The suggestion that an isolated population of the ancient humans may have been subject to island dwarfing has renewed scientific interest in this curious evolutionary process. This project addresses one of the many unanswered questions related to dwarfing: How does skull shape respond to a significant reduction in body size, particularly in an animal for which brain size is presumably so important? This research will contribute to our understanding of basic mechanisms of evolution, with implications for human history and for the conservation ecology of endangered island species today.

许多哺乳动物都出现了孤立种群体型在物种层面上的缩小（矮化），甚至可能影响到我们的一些原始人类亲戚。 岛屿矮化的常见颅后相关性已被记录，但对于头骨的形状及其许多集成组件如何受到影响的详细研究却很少。 该项目将检查几个岛屿物种的博物馆标本，这些物种与祖先相比体型较小，以表征头骨大小和形状的差异。将使用多种尺寸和形状指标（包括 3D 几何形态测量学方法）对几种特有灵长类动物的颅面形态进行量化，并与密切相关的大陆灵长类动物进行比较。 回归分析将在适当的时候解释系统发育。 此外，食肉动物岛屿矮化的例子将提供非灵长类动物的比较案例。这些种间比较的目的有三个。 首先，该研究将确定与现存灵长类物种样本中岛屿矮化相关的颅面形态的变化。 其次，它将通过测试形状、大小和脑化程度的差异来确定岛屿矮人种群相对于大陆矮人种群的共同点。 每种情况下的零假设都是基于先前对相关分类群的研究的异速生长预测条件（对于给定的体型）。 最后，该项目将利用目标 1 和 2 的发现来阐明对弗洛勒斯原始人类遗骸的解释，这些遗骸表现出明显出乎意料的颅面比例。 在已知的岛屿矮化案例中，对头骨形状的定量表征将有助于深入了解这一过程的机制及其对已灭绝的原始人谱系成员可能产生的影响。尽管侏儒猛犸象和巨型啮齿动物等进化奇特动物一直引起研究人员的兴趣，但自从2017年在弗洛勒斯岛上发现了一个体型小、大脑小的人类遗骸以来，它们最近引起了人们的关注。 印度尼西亚。 古代人类的一个孤立种群可能遭受了岛屿矮化的影响，这一说法重新引起了科学界对这一奇怪进化过程的兴趣。 该项目解决了与侏儒化相关的许多悬而未决的问题之一：头骨形状如何应对身体尺寸的显着减小，特别是对于大脑尺寸可能如此重要的动物来说？ 这项研究将有助于我们理解进化的基本机制，对人类历史和当今濒临灭绝的岛屿物种的保护生态具有影响。