Collaborative research: A histological and CT study of midfacial growth trajectories in subadult primates

灵长类与大多数其他哺乳动物的不同之处在于面部中部缩小的趋势，最明显的是猴子、猿和人类的鼻子缩小。这项研究使用一种新的发育方法来测试灵长类动物面部中部颅骨的缩小是否是邻近结构(例如眼睛和牙齿)生长的副产品。例如，对早熟视觉神经系统的选择是否从根本上影响了面中部的生长模式？比例较大的上颌乳牙及其继承者对上颌副鼻腔的发育是否有短暂或持久的影响？为了回答这些问题，将对70多个标本(包括20种灵长类动物)的身体样本进行研究。不同出生年龄的样本将使用高分辨率计算机断层扫描(CT)和脱钙样本的显微镜研究的创新组合进行研究。其结果是一种新的方法来绘制三维的骨沉积和骨吸收区域。该项目将创建与头部功能单位(眼睛、鼻道、牙齿)相关的灵长类头骨的独特三维“生长地图”。然后，将比较眼睛会聚程度不同(向前)的灵长类动物的三维头骨形状和生长地图。对神经和牙齿发育的间接影响，如孕期和饮食，也将被用作变量。这项研究的更广泛影响包括基于网络的图谱和来自标本的组织学和CT图像的数字档案。互动式在线地图集将作为解剖学家和灵长类动物学家的资源，前者将受益于人类发育各方面的动物模型，后者将受益于灵长类发育的资源。此外，还将制作动画，突出生长机制对进化适应的重要性，并将其作为在线教育工具提供给高级K-12学生及其教师。

Primates are distinguished from most other mammals by a trend toward midfacial reduction, most notably seen in the reduced 'snout' of monkeys, apes, and humans. This study uses a novel developmental approach to test whether midfacial reduction of the skull in primates is a byproduct of growth of neighboring structures (e.g., eyes and teeth). For example, does selection for a precocious visual nervous system fundamentally affect midfacial patterns of growth? Do proportionately large deciduous maxillary teeth and their successors have transient or lasting effects on development of paranasal spaces of the maxilla? To answer these questions, cadaveric samples from over seventy specimens (including 20 species of primates) will be studied. Specimens of different postnatal ages will be studied using an innovative combination of high-resolution computed tomography (CT) and microscopic study of decalcified samples. The result is a novel approach for mapping regions of bone deposition and resorption in three dimensions. The project will create unique three-dimensional 'growth maps' of primate skulls in relation to functional units of the head (eyes, nasal airways, teeth). Three-dimensional skull form and growth maps will then be compared among primates that differ in the extent to which the eyes are convergent (forward-facing). Indirect influences on neural and dental development, such as gestation length and diet, will also be used as variables.The broader implications of the study include a web-based atlas and digital archive of histological and CT images from the specimens. The interactive online atlas will be developed as a resource for anatomists, who will benefit from animal models for aspects of human development, and primatologists, who will benefit from the resource on development of primates. In addition, animations which highlight the importance of growth mechanisms for evolutionary adaptation will be created and made available to advanced K-12 students and their teachers as online educational tools.