Dissertation Research: The Functional Significance of the Anthropoid Postorbital Septum

本研究的主要目的是阐明被称为眶后隔的解剖结构的作用。这是一层薄薄的骨头形成了眼眶后部的侧面。这显然是一个最近进化的结构，只在类人猿（高等灵长类动物）和眼镜猴的头盖骨中发现。虽然眶后间隔多年来一直被用作高等灵长类动物的诊断标准，但实际上并没有对提出的解释其存在的各种假设进行测试。pi将进行各种各样的实验，试图解释这种性状的进化。一种已被提出的解释是，这块骨片的作用是将参与咀嚼的肌肉（位于鼻中隔后部的肌肉）与参与视觉的前肌分开。这可能对类人猿等高度视觉导向的动物具有重要意义。pi将对包括类人猿在内的许多动物进行解剖，以确定各种咀嚼肌相对于轨道的位置。结果将被绘制并作为预测工具进行检查。另一种已被提出的解释将鼻中隔与咀嚼时面部紧张的减少联系起来。骨应力的测量可以在Yerkes灵长类动物中心使用一系列动物进行。这项研究将有助于测试和澄清数百万年前使骨隔形成的力量，并了解其在当今动物中的功能。

The primary objective of this research is to clarify the role of an anatomical structure known as the postorbital septum. This is a thin sheet of bone which forms the lateral aspect of the rear of the orbit. It is apparently a recently evolved structure which is only found in the cranium of the anthropoids (the higher primates) and the tarsier. While the postorbital septum has been used as a diagnostic criterion of the higher primates for many years, there have been virtually no tests of the various hypotheses which have been put forward to account for its existence. The PIs will undertake a variety of experiments in an attempt to account for the trait's evolution. One explanation which has been advanced is that the sheet of bone serves to isolate muscles which are involved in mastication (those in back of the septum) from the anterior muscles which are involved in vision. This would presumably be of significance to highly visually-oriented animals such as the anthropoids. The PIs will undertake a number of dissections of animals, including anthropoids, to determine the placement of various masticatory muscles relative to the orbit. Results will be plotted and examined as a predictive tool. Another explanation which has been advanced relates the septum to the reduction of strain in the face during mastication. Measurements of bone stress can be carried out using a series of animals already at the Yerkes Primate Center. This research will help to test and clarify the forces which brought the bony septum into existence millions of years ago and understand its functioning in animals today.