Expanding our horizons in understanding brain and dietary evolution in Primates and their kin

拓展我们的视野，了解灵长类动物及其亲属的大脑和饮食进化

• 批准号: RGPIN-2022-03073
• 负责人: Silcox, Mary
• 金额: $ 2.4万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743617
• 关键词: Expanding; our; horizons; understanding; brain; Expanding; our; horizons; understanding; brain

The evolution of the diet is central to the process of primate origins. All of the competing scenarios for primate origins have a dietary component: visual predation focusing on adaptations for insectivory; terminal branch feeding involving an expansion of the arboreal dietary niche to include more fruit; and the grasp-leaping hypothesis, which incorporates a shift to greater herbivory in early primate evolution. Diet is of particular importance in understanding the evolution of the enlarged and complex primate brain. Building such a brain requires access to high energy food, while retrieving such broadly dispersed and irregularly available foodstuffs (e.g., fruit) requires greater degrees of processing power. Although analyses of modern primates have supported the important role of diet in brain evolution, they necessarily simplify the origin of primates down to a single node. The fossil record demonstrates that there were many lineages of stem primates, making it clear that the story is much more complex than the idealized version implied by such studies. Although there have been strides in recent years, there are still several lineages of early primates for which no quantitative work has been done to estimate aspects of diet. A critical component of this shortfall is that early primates have patterns of adaptations not found among living primates, meaning that living members of the order are insufficient models for reconstructing diet in those groups. The current study will seek to fill some of these gaps by considering a much broader range of model taxa and by using cutting edge dental topographic methods to allow for precise quantification of dental form. This study will also seek to expand the types of information that can be collected and compared with respect to the early evolution of the brain in primates. The strong evidence for rampant parallelism in primate brain size evolution implies that studies that are limited to living taxa will be constrained in reconstructing the size and shape of the brain in the common ancestor of all primates. This underscores the importance of fossils to an understanding of the early stages of primate brain evolution. Since the brain does not fossilize, the data available from even the best-preserved fossils is limited to the imprint of the brain preserved on the internal surface of the cranium (i.e., the endocast). The current study will seek to use geometric morphometric and DiceCT methods to expand the information about changing shape and function that can be extracted from such endocasts. Ultimately, the goal of this study will be to amass a dataset that will allow for a synthetic consideration of how shifting diets are aligned (or not) with changes in brain size and shape, using a phylogenetic framework that incorporates both fossil and extant members of Primates, and of closely related groups.

饮食的演变对于灵长类动物起源过程至关重要。灵长类动物起源的所有竞争场景都有饮食成分：视觉捕食，重点是适应昆虫动物；末端分支喂养，涉及树木饮食利基的扩张，包括更多的水果；以及在早期灵长类动物进化中向更大的草食主义者转变的抓住假设。饮食对于理解扩大和复杂的灵长类动物大脑的演变至关重要。建立这样的大脑需要获得高能量食品，同时检索如此广泛的分散和不规则的食品（例如水果）需要更大程度的加工能力。尽管对现代灵长类动物的分析支持了饮食在大脑进化中的重要作用，但它们必然将灵长类动物的起源简化为单个节点。化石记录表明，有许多STEM灵长类动物的血统，这清楚地表明，故事比此类研究所暗示的理想化版本要复杂得多。尽管近年来已经有了大步的进步，但仍有一些早期灵长类动物的血统尚未为估计饮食的各个方面进行定量工作。这一短缺的一个关键组成部分是，早期灵长类动物在活着的灵长类动物中没有发现适应模式，这意味着该秩序的活成员是重建这些群体饮食的模型不足。当前的研究将试图通过考虑更广泛的模型分类单元，并使用尖端牙齿地形方法来精确量化牙齿形式来填补这些空白。这项研究还将寻求扩大可以收集的信息类型，并将其与灵长类动物中大脑的早期演变相比。灵长类动物脑大小进化中猖ramp的平行性的有力证据表明，仅限于活类群的研究将受到重建所有灵长类动物共同祖先中大脑的大小和形状的限制。这强调了化石对理解灵长类动物大脑进化的早期阶段的重要性。由于大脑没有化石，因此即使是保存最完好的化石也可用的数据仅限于保存在颅内表面上的大脑的烙印（即内接收）。当前的研究将寻求使用几何形态计量学和分离方法来扩展有关可以从此类内生剂中提取的变化形状和功能的信息。 最终，这项研究的目的是积累一个数据集，该数据集将允许使用系统发育框架，同时结合了化石和现存的灵长类动物和密切相关的组，将饮食转移饮食如何与脑大小和形状变化相结合（或不）。