Development and morphological variation in Pongo pygmaeus

本研究主要探讨了野生矮猩猩颅、齿系和后颅的发育模式。本研究所调查的骨骼部位包括：牙齿萌出和磨损过程、颅缝、长骨近端和远端关节、锁骨、骨盆。作为尺寸变量，还测量了牙列、颅骨和长骨的尺寸。对牙齿和几个骨骼关节发育阶段的分析揭示了猩猩发育的几个不同方面。这些措施如下所列。牙齿的发育、成熟和老化、颅骨、后颅骨或多或少独立发生，尤其是在男性中。因此，对成人的界定应慎重。2.颅底缝（蝶枕结合）仅在恒牙列萌出完成后闭合，有时磨牙会出现严重磨损。3.最后完成发育的后颅部是前肢的末端。尺桡骨远端连线发生在颅底缝闭合后。颅和颅后的发育、成熟和衰老受内分泌因素控制，而内分泌因素又可能与社会行为有关。为了更好地了解这些相互作用，有必要对圈养猩猩进行纵向研究，同时研究形态学，内分泌学和行为学变量。此外，为了接近猩猩这种发育模式的进化和适应意义，对野生猩猩的研究，其中形态和繁殖成功之间的关联是必要的。

This research focused on the developmental patterns of crania, dentition, and postcrania among wild Pongo pygameus. Skeletal parts investigated in this study were as follows : tooth eruption and wear progress, cranial sutures, proximal and distal joints of long bones, clavicle, pelvis. As size variables, size of dentition, cranial, and long bones were also measured. Analysis of developmental stages of teeth and several skeletal joints revealed the several distinct aspects of orangutan development. Those are listed below.1. Development, maturing and aging of teeth, crania, postcrania occur more or less independently, especially in males. Therefore, the definition of adult should be done carefully. 2. Basal cranial suture (spheno-occipital synchondorosis) closes only after the completion of eruption of permanent dentition, and sometimes, molars show heavy wear by then. 3. The last postcranial parts to finish development are distal ends of forelimbs. The line of distal end of ulna and radius happens after the closure of basal cranial suture. Development, maturing and aging of crania and postcranial are supposed to be controlled by endocrinological factors which are in turn related probably with social behavior. In order to have better understanding of these interactions, it is necessary to carry out longitudinal study on captive orangutans in which morphological, endocrinological and behavioral variables should be studied at the same time. In addition, in order to approach the evolutionary, and adaptive significance of such developmental patterns of orangutans, a study of wild orangutans in which association between morphology and reproductive success is necessary.