Deane Andrew, Agosto Elizabeth R
Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Department of Anthropology, Indiana University-Indianapolis, Indianapolis, Indiana, USA.
Anat Rec (Hoboken). 2025 Sep;308(9):2469-2489. doi: 10.1002/ar.25619. Epub 2025 Jan 7.
Diet is one of a limited set of key ecological parameters defining primate species. A detailed understanding of dental functional correlates with primate diet is a key component for accurate dietary inference in fossil primates. Although considerable effort has been devoted to understanding post-canine dental function, incisor function remains poorly understood. Prior analyses have demonstrated that anthropoid incisor mesiodistal (MD) and cervico-incisal (CI) crown curvature correlates with an increased reliance on frugivory and that greater incisor crown curvature functions to increase total crown area and, by extension, crown resistance to normal bending stresses (e.g., compressive and tensile forces). The present study investigates the correlation between incisor basal cross-sectional area at the cementoenamel junction (CA) and the degree to which taxa rely on frugivory to better understand how non-normal forces (e.g., shear) may influence incisor morphology. Results demonstrate that, like resistance to bending stress, resistance to shear stress (as represented by the CA), is positively correlated with an increased reliance on frugivory such that more frugivorous anthropoids have larger CA relative to body mass and therefore greater resistance to shear stress. Likewise, hard-object frugivores have increased shear resistance relative to soft-object frugivores. A more detailed working understanding of the forces acting on primate incisors, and how these crowns resist those forces, will contribute to improving our understanding of how diet influences incisor morphology and the accuracy of dietary inference in fossil anthropoids.
饮食是定义灵长类物种的一组有限关键生态参数之一。深入了解与灵长类饮食相关的牙齿功能是准确推断化石灵长类动物饮食的关键组成部分。尽管人们已经付出了相当大的努力来理解犬齿后的牙齿功能，但对门齿功能的了解仍然很少。先前的分析表明，类人猿门齿近远中（MD）和颈切缘（CI）冠曲率与对果实食用的依赖增加相关，并且更大的门齿冠曲率起到增加总冠面积的作用，进而增加冠对正常弯曲应力（如压缩和拉伸力）的抵抗力。本研究调查了釉牙骨质界处门齿基部横截面积（CA）与分类群对果实食用的依赖程度之间的相关性，以更好地理解非正常力（如剪切力）如何影响门齿形态。结果表明，与对弯曲应力的抵抗力一样，对剪切应力的抵抗力（以CA表示）与对果实食用的依赖增加呈正相关，因此更多以果实为食的类人猿相对于体重具有更大的CA，从而对剪切应力具有更大的抵抗力。同样，硬果食者相对于软果食者具有更高的抗剪切力。更详细地了解作用于灵长类门齿上的力，以及这些牙冠如何抵抗这些力，将有助于提高我们对饮食如何影响门齿形态以及化石类人猿饮食推断准确性的理解。
