Doctoral Dissertation Improvement: Ecological and Morphological Correlates of Infraorbital Foramen Size: Paleontological Implications

博士论文改进：眶下孔大小的生态和形态学相关性：古生物学意义

• 批准号: 0622422
• 负责人: Liza Shapiro
• 金额: $ 1.18万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0622422&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Improvement; Ecological; Morphological

The evolutionary origin of primates has attracted considerable attention over the past century. Several competing hypotheses have been proposed to account for the evolutionary divergence of primates from other mammals. These hypotheses emphasize the importance of variables such as diet, substrate preference, and activity pattern when reconstructing the behavioral and ecological profiles of extinct primates and their predecessors. Morphological analyses of cranial features are frequently employed to test these hypotheses. The infraorbital foramen (IOF) is one morphological feature that has been used in this capacity. The IOF is located below the inferior orbital margin of the maxilla (face). The infraorbital nerve (ION) passes through the IOF, and transmits sensory information from specialized touch cells (mechanoreceptors) of the upper lip, rhinarium, and vibrissae to the brain. For decades, researchers have used the size of the IOF to assign evolutionary relationships and ecological profiles to fossil primates. However, these interpretations are based on untested assumptions linking IOF size to ION size, vibrissal development, and ecology. The purposes of this doctoral dissertation research project are to establish what IOF size indicates functionally and ecologically and to apply the results to the fossil record in order to evaluate competing hypotheses proposed for the origin of primates. The doctoral student hypothesizes that behavioral and ecological differences among mammals directly affect facial sensory acuity (maxillary mechanoreceptivity) and that the size of the IOF is a measure of relative sensory acuity of the face among mammals. This study poses three questions that will assist in appraising this hypothesis. 1) Does IOF size correlate with IOF area, ION area, and vibrissa number? 2) How does ecology (e.g., diet) affect IOF size? 3) How does IOF size in primates compare to that of other mammals? Data on IOF/ION area and vibrissa counts will be collected on a phylogenetically and ecologically diverse sample of mammalian cadavers, osteological museum specimens and skin pelts, representing 18 mammalian orders. Once the relationships among IOF area, maxillary mechanoreception, and ecology are determined among extant mammals, the results will be applied to questions regarding the evolution and diversification of primates. Testing these hypotheses is difficult at times, given the fragmentary nature of the fossil record. However, the IOF is one anatomical feature that is frequently preserved in fossilized remains. Therefore, the results of this study will allow for an expansion of previous paleoecological analyses and will enhance our current understanding of the evolution of early primates.In terms of broader impacts, this project will help train a graduate student. Because the questions addressed in this study will be explored using a diverse mammalian sample, the determined correlates of IOF size will be applicable to evolutionary questions in both paleoanthropological and general mammalian paleontological research.

在过去的一个世纪里，灵长类动物的进化起源引起了相当大的关注。为了解释灵长类动物与其他哺乳动物在进化上的差异，人们提出了几个相互竞争的假设。这些假设强调了在重建已灭绝灵长类动物及其祖先的行为和生态概况时，饮食、基质偏好和活动模式等变量的重要性。颅特征的形态学分析经常被用来检验这些假设。眶下孔（IOF）是一种形态学特征，已被用于此功能。IOF位于上颌骨（面部）下眶缘下方。眶下神经（ION）穿过IOF，将来自上唇、鼻鼻和触须的特殊触觉细胞（机械感受器）的感觉信息传递到大脑。几十年来，研究人员一直使用IOF的大小来分配灵长类化石的进化关系和生态概况。然而，这些解释是基于未经验证的假设，将IOF大小与离子大小、振动发展和生态联系起来。本博士论文研究项目的目的是建立IOF大小在功能和生态学上的指示，并将结果应用于化石记录，以评估灵长类动物起源的竞争性假设。该博士生假设，哺乳动物之间的行为和生态差异直接影响面部感觉敏锐度（上颌机械感受性），而IOF的大小是衡量哺乳动物面部相对感觉敏锐度的一种指标。这项研究提出了三个问题，将有助于评估这一假设。1) IOF的大小是否与IOF面积、离子面积和触须数相关？2)生态环境（如饮食）如何影响IOF大小？3)与其他哺乳动物相比，灵长类动物的IOF大小如何？将对18个哺乳动物目的哺乳动物尸体、骨骼博物馆标本和皮肤毛皮进行系统发育和生态多样性取样，收集IOF/ION面积和触须计数数据。一旦确定了现存哺乳动物的上颌机械感受区、上颌机械感受区和生态学之间的关系，这一结果将应用于灵长类动物的进化和多样化问题。由于化石记录的碎片性，有时很难验证这些假设。然而，IOF是一个经常保存在化石遗骸中的解剖学特征。因此，这项研究的结果将允许扩展以前的古生态分析，并将加强我们目前对早期灵长类动物进化的理解。就更广泛的影响而言，这个项目将有助于培养一名研究生。由于本研究中提出的问题将使用不同的哺乳动物样本进行探索，因此确定的IOF大小的相关性将适用于古人类学和一般哺乳动物古生物学研究中的进化问题。